Download A Web GIS on Volcanoes of the World: Current Status, Monitoring

A Web GIS on Volcanoes of the World:
Current Status, Monitoring, Historical Activity and Catalog
Matt Stuemky
Geography 591 - Web GIS
Dr. Jennifer Swift
University of Southern California
Geographic Information Science & Technology Program
May 3, 2009
Aerial photo of the Mount Redoubt volcano in Alaska, April 2009.
(Photo source: U.S. Geological Survey – Volcano Hazards Program – Alaska Volcano Observatory)
Introduction
Volcanoes can be a source of both fascination and fear. When contemplating volcanoes from the
fascination standpoint, one can’t help but admire the aesthetic beauty that many of them possess, whether
seen from an airplane, up close from ground level, or for those who have done so, when climbing the steep
flank of an active volcano in order to eventually stand at the edge of a steaming crater. The primary
motivation to create an interactive web map application on volcanoes came about because of a general
interest in natural hazards and the impacts they have on people and places. Studying volcanic activity in a
variety of ways, from reading recent news coverage on the currently erupting Redoubt volcano in Alaska, to
having personal experiences climbing several different active volcanoes in New Zealand and Mexico, served as
inspiration to develop the Volcanoes of the World interactive web map.
In a recent article in The Week Magazine, Keeping a Wary Eye on Volcanoes (2009), the author
emphasizes the fear aspect. The article focuses on the eruptive potential of several volcanoes within the
United States, and the ongoing monitoring efforts of agencies such as the U.S. Geological Survey. One
example mentioned in the article is the Yellowstone volcanic region in Wyoming, indicated by geologists to be
a place of particular concern. Many people may not even realize that Yellowstone is much more than a
collection of thermal geysers and hot springs, it is in actuality a very large caldera, a seismically active region
which has a history of massive volcanic eruptions on average every 600,000 years. It has been over 640,000
years since it last erupted violently. Regarding the likelihood of a devastating, worldwide-affecting eruption of
Yellowstone, the author states, “Some geologists are worried that it might be sooner rather than later…it
could happen next week—or possibly 50,000 years from now. Whenever it happens, it could potentially be a
cataclysm affecting everyone in the entire U.S. and the world.” (Keeping a Wary Eye on Volcanoes, 2009)
Significant volcanic eruptions such as Mount Saint Helens in Washington State in 1980, and Mount
Pinatubo in the Philippines in 1991 are still relatively fresh in people’s memories. These two events pale in
size compared to Yellowstone's past eruptions, yet they nevertheless demonstrated how volcanic eruptions
not only have an immediate and destructive impact on people, infrastructure and economies living nearby but
they can also have a long term impact worldwide, often for months or years, such as the climate effects
caused by volcanic ash.
P a g e 1 | Matt Stuemky
Project Implementation Goals
Each year, natural hazards, whether volcanoes, earthquakes, tsunamis, hurricanes or other type, take a
huge toll in deaths, injuries, property damage, and economic loss. Dunbar (2007) states, “Much of this
devastation can be reduced through existing mitigation techniques and greater public awareness of them. If
people are aware of the risks from natural hazards faced by their communities, they are more likely to take
steps to reduce potential losses.”
The intent of this project was not to create an overly technical web GIS designed as an analysis tool for
mapping volcano geomorphology, volcanic ash cloud dispersion modeling or a myriad of other technical facets
of volcanoes. Such web maps can be found online, developed for academic and scientific research projects
conducted by geologists and other specialists. These web maps typically focus on a specific volcano or
volcanic region. The Volcanoes of the World web GIS is instead designed to be an educational tool and
information resource for the general public.
Dunbar (2007) writes about the importance of making available to the general public a variety of easyto-use, Internet-based resources for studying natural hazards, using (among other techniques) interactive
maps as a tool to provide an integrated web-based GIS. She further states these web GIS should utilize
databases containing earthquake, tsunami, and volcano information, as well as additional auxiliary geospatial
data. The project implementation goals outlined below for the Volcanoes of the World project came about in
part from some of Dunbar’s ideas of developing creative ways to use available online resources on natural
hazards in order to both stimulate interest and to educate people.
Extensive research has made it evident that very few volcano-themed web map applications exist. The
ones that happen to feature volcanoes in some way do not seem to take full advantage of data sources that
are available online. Some feature current activity reports issued by the U.S. Geological Survey and the
Smithsonian Institution. Other interactive web maps depict volcano locations around the world but do not
provide any current activity information. Fortunately, a variety of volcano-related datasets are freely available
to the general public, from a variety of organizations and in a variety of formats. The data sources identified
and implemented for this project, listed in Appendix A, represent only a portion of what is available online.
Amateur web map mash-ups on natural hazards typically focus on earthquake activity. Only a few of
these also include current volcano activity, typically shown as location markers on a map, but offer little else in
the way of detailed information. Several professionally developed natural hazard themed web map
applications do exist but, as with the amateur mash-ups, volcano information is not strongly emphasized
beyond location identification. Two web GIS run by U.S. government agencies are the USGS Natural Hazards
P a g e 2 | Matt Stuemky
Support System (http://nhss.cr.usgs.gov) and the NGDC’s Natural Hazards system
(http://map.ngdc.noaa.gov/website/seg/hazards/). Unfortunately, both web maps provide little or no current
activity information on volcanoes. Alerts and current status information on earthquakes, wildfires, hurricanes,
and severe weather seem to be more prominently featured on these web maps.
Whether amateur or professional, no web GIS seems to exist that includes a volcano monitoring
feature. Basic volcano monitoring can be incorporated into a web GIS by making use of some near real-time,
remotely sensed satellite imagery as described by Davies (2007) and Krueger (2006). Also, live webcams
pointed at volcanoes was determined to be another useful monitoring feature.
Databases containing historical activity of volcanoes are currently available from the National
Geophysical Data Center (NGDC) as discussed by Dunbar (2007) and Peduzzi (2005). According to Guffanti
(2007), the U.S. Geological Survey is also working towards making historical databases available to the general
public. Research turned up no web GIS that directly incorporates volcanic eruption history data from the
NGDC, other than the natural hazards web GIS application on the NGDC website itself.
Since other web GIS applications appear to only utilize one or two data sources on volcanoes, the main
goal of the Volcanoes of the World project was to try to consolidate a variety of volcano-related data and
display spatially-referenced features on a single, unified web map, using a simple, easy-to-use interface. The
following five implementation goals were established for the project:
1)
Current Status: provide the ability to show on the web map the locations and status reports of new
and ongoing volcanic activity around the world based on information provided by the U.S.
Geological Survey, Volcanic Ash Advisory Centers, and the Smithsonian Institution
2)
Monitoring: integrate several near real-time, remotely sensed datasets designed to provide indicators
of both new and ongoing volcanic activity around the world using data sources from several
different organizations; integrate live webcams pointed at volcanoes as an additional monitoring
feature
3)
Historical Activity: provide the ability to identify locations and view summary reports of significant
volcanic eruptions around the world using volcanic eruption history datasets from the NGDC
4)
Volcano Catalog: provide the ability to easily search a catalog of volcanoes by name, geographic
location, and/or type (cinder cone, shield volcano, stratovolcano, etc.) using a small relational
database; display search results directly on the web map; provide summary information and a
photo (if available) of the volcano and a direct link to more detailed information on the Smithsonian
Institution Global Volcanism Program website
5)
Other Layers: incorporate additional spatially-enabled datasets as optional overlays to the web map
including earthquake activity, volcano activity news, and special thematic base maps
P a g e 3 | Matt Stuemky
Technology
In addition to the implementation goals outlined in the previous section, the choice of web GIS
technology used is the other major goal of the project: to what extent possible, utilize open source solutions
rather than proprietary ones. The Volcanoes of the World web map application was designed in part as an
attempt to significantly improve upon the user interfaces offered by other natural hazard themed web GIS,
including the ones from the USGS and NGDC. Both systems use ArcIMS web mapping software from ESRI.
Although intended to be comprehensive web applications, both are slow at displaying map features and are
hindered with a somewhat dated user interface. Utilizing dynamic client-side web technologies such as Ajax
combined with the popular Google Maps interface was deemed to be a desirable goal to make the Volcanoes
of the World web map easy to use, responsive, and appealing to look at. The following list summarizes the key
technology used for the project:

Open source web mapping software: Google Maps API version 2.x with Ajax extensions

Web programming languages: HTML, client-based JavaScript, server-based PHP with Curl extensions

Vector point and line map features: multiple approaches used to process XML, KML, ASCII text, and
GeoRSS
datasets;
a
third-party
Google
Maps
API
extension
called
GeoXML
(http://code.google.com/p/geoxml/) is used to process some of the data sources; all other point and
line data are handled using native Google Maps API functions combined with JavaScript and PHP code

Raster map features: Google Maps API GTileLayer and GMapType objects and JavaScript code used to
retrieve and process raster datasets from WMS resources; raster datasets used for near real-time
monitoring (i.e. satellite remote-sensed imagery as atmospheric indicators of volcanic activity) and for
several additional thematic map types (i.e. world population density)

Open source database: MySQL; an existing MySQL database called GIS located on the production web
server was used for the implementation of the Volcano Catalog

Web server hardware: Microsoft IIS for both development and production servers

Applications and tools for project development:
o
o
o
o
o
o
o
Web browsers: Mozilla Firefox and Microsoft Internet Explorer
Web programming (HTML, JavaScript, PHP): Adobe Dreamweaver CS4
Web page debugging: Firefox – built-in Error Console tool and Firebug third-party extension; Internet
Explorer – built-in script debugger tool
Database administration: Navicat for MySQL, MySQL Administrator, MySQL Query Browser
Web server management: Internet Information Services (IIS) Manager on development server,
Webhost4Life Control Panel web-based site management tools on production server
Microsoft Excel: modify data used for the Volcano Catalog, import data into the MySQL database
Microsoft Paint and Paint.NET: create and modify map icons and other images used for the web map
application
P a g e 4 | Matt Stuemky
Implementation: Current Status
The first and most important feature of the Volcanoes of the World project is one that prominently
displays the locations of all actively monitored volcanoes that have new or ongoing activity, ones that have
been issued alerts and have current status reports associated with them (Guffanti, 2007). Similar to the U.S.
Geological Survey, government agencies in other countries are often tasked with monitoring historically active
volcanoes and to issue public alerts and status reports as needed. However, it was beyond the scope of this
project to try and incorporate all these data sources into the web map application. Instead, the goal was to
utilize several of the most readily available data sources from the following three organizations: for volcanoes
within the United States and its territories, the U.S. Geological Survey Volcano Hazards Program (USGS VHP);
for all other volcanoes located around the world, the Volcanic Ash Advisory Centers (VAACs) and the
Smithsonian Institution Global Volcanism Program (GVP). All volcano status summary and report information
for a volcano is displayed directly on the map canvas simply by clicking a marker icon.
Figure 1 below shows the first full implementation, Current Status, for the Volcanoes of the World web
map. It depicts three different marker icons on the map, placed over the location of the Mount Redoubt
volcano in Alaska. The USGS VHP and VAACs issue alerts and current status reports on a daily basis compared
to the once-a-week updates from the Smithsonian Institution GVP. When the map is zoomed out to a small
scale view, marker icons from the more frequently updated datasets will always be superimposed over the
less frequently updated ones, but only in situations where multiple organizations have current status
information for a particular volcano. Zooming in to a large scale view of a volcano, as shown in Figure 1, will
make all marker icons accessible so the user can easily select each one individually.
Figure 1 – first implementation example of the Volcanoes of the World web map: Current Status
information from the USGS Volcano Hazards Program, Volcanic Ash Advisory Centers and Smithsonian
Institution Global Volcanism Program; marker icons are placed on the web map in the vicinity of the
Redoubt volcano
P a g e 5 | Matt Stuemky
U.S. Geological Survey – Volcano Hazards Program
The U.S. Geological Survey (USGS) operates five independent Volcano Observatories: Alaska (AVO),
Hawaii (AVO), Cascade Range (CVO), Yellowstone (YVO), and Mariana Islands (CNMI). Collectively, these
observatories make up the USGS Volcanic Hazards Program (VHP). The VHP recently adopted a common
National Volcano Early Warning System used for characterizing the level of unrest and eruptive activity of the
approximately 170 volcanoes that the USGS VHP monitors within the United States and its territories. To
provide a way of indicating whether or not a volcano has been elevated in status, based on either new or
ongoing levels of unrest, this system implemented by the USGS VHP uses volcano alert level designations of
Warning / Watch / Advisory / Normal / Unassigned combined with aviation (volcanic ash) color-code
designations of Red / Orange / Yellow / Green. (Guffanti, 2007)
As shown in Figure 2 below, the Current Status menu as implemented on the Volcanoes of the World
web map identifies the specific icons used by the USGS VHP to indicate the current status of all volcanoes
monitored within the United States and its territories.
Figure 2 – Current Status menu
P a g e 6 | Matt Stuemky
The USGS VHP website uses a simple Google Maps interface to depict all monitored volcanoes. The
maps emphasize volcanoes with an elevated alert status. Examples of these are the Cleveland and Redoubt
volcanoes in Alaska and the Kilauea volcano in Hawaii. Additionally, several volcanoes currently at a Normal or
Unassigned status are emphasized more prominently (by using larger-sized icons) on the USGS VHP web maps
compared to all other volcanoes with the same Normal/Unassigned designation. This is because they are
currently being more actively monitored than the others. In some cases it is because they have been raised to
higher alert levels at various times in recent years because of eruption activity. Examples of these are
Yellowstone in Wyoming and the Anatahan volcano in the Northern Mariana Islands region of the western
Pacific Ocean. (USGS VHP, 2009; Guffanti, 2007)
The USGS VHP web maps use two different XML files containing vector point data used to identify the
locations of all these monitored volcanoes. The Volcanoes of the World web map utilizes these same two XML
files as data sources. Using the Google Maps API, these two files are downloaded directly from the USGS
Volcano Hazards Program web server the first time the Volcanoes of the World web map loads. JavaScript
code is used to automatically parse the data and display onto the map a series of marker icons that
correspond exactly to the volcano alert level/aviation color code icons used by the USGS VHP.
As shown in Figure 3 below, clicking these icons will display a pop-up information window showing
summary and status information as well as a direct link to a volcano’s current status page on the USGS VHP
website. All data shown in the pop-up information window is derived from the contents of the two XML files.
Figure 3 – U.S. Geological Survey Volcano Hazards Program, Current Status on Redoubt volcano
P a g e 7 | Matt Stuemky
Volcanic Ash Advisory Centers
Volcanic ash is a significant hazard to aviation. To ensure safe navigation for aircraft and monitor
climatic impact, nine regional Volcanic Ash Advisory Centers (VAACs) have been established around the world.
Two VAACs exist within the United States, in Washington DC and in Anchorage Alaska. Both VAACs are part of
the National Oceanic and Atmospheric Administration (NOAA). All nine VAACS worldwide are tasked with
tracking volcanic eruptions, in particular, monitoring all available satellite imagery for volcanic ash clouds. The
VAACs issue several products whenever volcanic eruptions are detected. One of these is the Volcanic Ash
Advisory Statement (VAAS), which includes text describing current volcanic activity and ash cloud position
(Dunbar, 2007). As shown in the Current Status menu in Figure 2 above, the different colors of the marker
icons used on the map are based on the alert level associated with the VAAS, either Red (Warning), Orange
(Watch), Yellow (Advisory) or Grey (not assigned).
The Darwin Volcanic Ash Advisory Centre, part of the Australian Bureau of Meteorology, consolidates
and disseminates all active Volcanic Ash Advisory Statements (VAAS) issued from the nine different VAACs.
The VAAS are issued via XML-based text products, including CAP alert feeds, Atom RSS feeds, and a KML file
which are all continuously updated (refer to Appendix A: Data Sources).
The KML file was selected for implementation into the Volcanoes of the World web map. The file is
automatically downloaded the first time the web page loads and, using Google Maps API functions and
JavaScript code, the data is parsed and displayed on the web map using unique, color-coded marker icons. As
shown in Figure 4 below, clicking any of these markers will display a pop-up window containing the report
summary as well as a direct link to the associated CAP alert page where additional information can be viewed.
Figure 4 – Volcanic Ash Advisory Centers, Volcanic Ash Advisory Statement on Redoubt volcano
P a g e 8 | Matt Stuemky
Smithsonian Institution – Global Volcanism Program
The U.S. Geological Survey collaborates with the Smithsonian Institution Global Volcanism Program to
produce Weekly Volcanic Activity Reports, which are published on the GVP website itself as well as
disseminated using an RSS data feed. The GVP weekly reports offer short summaries on both new and
ongoing volcanic activity worldwide. More extensive monthly reports that incorporate images, graphics and
monitoring data are also published on the GVP website (Guffanti, 2007) but are not available as an RSS feed or
other type of dataset.
The RSS dataset containing the Weekly Volcanic Activity Reports was selected for implementation into
the Volcanoes of the World web map. Similar to the USGS VHP and VAAC data handling operations, the GVP
data is loaded and processed the first time the web page loads and, using Google Maps API functions and
JavaScript code, the data is parsed and displayed on the web map. As shown in Figure 5 below, a unique
marker icon is used to represent each volcano that has a weekly status report issued by the Smithsonian
Institution Global Volcanism Program.
Figure 5 – Smithsonian Institution Global Volcanism Program, Weekly Status Report on Redoubt volcano
P a g e 9 | Matt Stuemky
Implementation: Monitoring
The second major implementation of the Volcanoes of the World project was to include the ability to
perform some basic monitoring of volcanic activity. A variety of datasets are available on the Internet that
originate from numerous ground-based seismic, thermal and gas emission sensors installed on or near active
volcanoes such as the Kilauea volcano in Hawaii (Davies, et al., 2008). However, a more practical, broad-based
approach was sought, considering the scope and time constraints of this project. The solution was to utilize
public datasets derived from satellite imagery, ones that can ideally be used to provide indicators of volcanic
activity suitable for monitoring any volcano located around the world. In addition, the decision was made to
incorporate a dataset of live webcams, specifically ones that are pointed at volcanoes, as an additional
monitoring component for the web map application.
Regarding the use of remotely-sensed data, Krueger (2006) describes in detail the so-called A-Train, a
system of NASA satellites and the various different types of measuring instruments installed on board them.
These instruments are used by scientists and researchers for a variety of studies including near real-time
monitoring of volcanoes worldwide. Many of the details from Krueger’s presentation served as the basis for
seeking out and obtaining datasets that contained this remotely-sensed imagery for the Volcanoes of the
World web map.
To implement the goal for a basic volcano monitoring, two types of near real-time, satellite remotesensed datasets were sought: those that provide atmospheric indicators and those that provide ground level
thermal (hot spot) indicators. Volcano webcams are the third type of monitoring that was implemented.
Figure 6 below shows the Monitoring menu as implemented for the Volcanoes of the World web map.
Figure 6 – Monitoring menu
P a g e 10 | Matt Stuemky
1. Atmospheric indicators
As described by Krueger (2006), NASA maintains a powerful and diverse array of atmospheric monitoring
instruments on board several different satellites. Research for this project made it evident that a large
amount of publically-accessible satellite imagery was available. It was also clear that it was beyond the scope
of this project to attempt to utilize all the available datasets. Organizations in both the public and private
sector provide many different remotely-sensed datasets that could potentially be useful for volcano
monitoring. However, further research revealed that several online resources such as those provided by
NASA's Jet Propulsion Laboratory (JPL) and Goddard Earth Sciences Data and Information Services Center (GES
DISC) provided more convenient access to the satellite imagery compared to others.
For the atmospheric indicators monitoring component of the Volcanoes of the World web map, remote
sensed imagery derived from several NASA satellite instrument systems were initially identified for
implementation. These included the MODIS, AIRS and OMI instruments, as described below. All of these,
except for the OMI-based datasets, were eventually implemented into the web map successfully.
MODerate Resolution Imaging Spectroradiometer (MODIS) instrument: visual imagery
Near real-time satellite imagery of the earth surface in the normal visual spectrum generally allows for
observation of volcanic activity. The MODIS “Daily Planet” dataset, showing current cloud coverage
worldwide, was selected as the primary atmospheric indicator monitoring layer for the web map. As with the
Blue Marble “Next Generation” thematic map type described later, this tiled raster dataset is retrieved from
the NASA Jet Propulsion Laboratory’s OnEarth WMS server. Earth is imaged continuously by the MODIS Terra
satellite, with all imagery between 6 to 24 hours old. (NASA JPL OnEarth, 2009)
Large volcanic eruptions can be relatively easy to identify using the MODIS “Daily Planet” dataset.
However, normal, meteorological clouds may still obscure volcanic emissions (water vapor, steam, volcanic
ash, etc.), especially with smaller, more short-term eruptions. If the volcano exhibits any sort of emissions
that show up on the visual satellite imagery, the color of the clouds emanating from the volcano can provide
some basic indicators of the type of emissions. For example, white-colored clouds generally indicate water
vapor and steam combined with SO2 gases as shown in Figure 7 below. Brown-colored clouds are more
indicative of volcanic ash (VA) as shown in Figure 8 below.
P a g e 11 | Matt Stuemky
Figure 7 – MODIS Terra “Daily Planet” image showing water vapor and steam cloud emissions from the
Fernandina volcano located on the Galápagos Islands off the coast of Ecuador
Figure 8 – MODIS Terra “Daily Planet” image showing volcanic ash (VA) cloud emissions from the Llaima
volcano located in southern Chile
Atmospheric InfraRed Sounder (AIRS) instrument: false color/infrared imagery and SO2
As part of the NASA Earth Observing System (EOS) project, the Aqua satellite was launched into Earth orbit
in May 2002. On board the satellite is the Atmospheric Infrared Sounder (AIRS) instrument, one of six available
monitoring instruments. AIRS data has been made available to the general public in various formats for
several years. NASA GES DISC operates a WMS server housing near real-time datasets from AIRS. (NASA GES
DISC, 2009) The following two datasets were selected for implementation in the Volcanoes of the World web
map:
P a g e 12 | Matt Stuemky
AIRS Near Real Time False Color (RGB) dataset
Using the visible channels of the AIRS instrument (ch3=red,ch2=green, ch1=blue) a false color image is
produced of land, but provides the ability to distinguish different cloud types over land and water (NASA GES
DISC, 2009) , including the unique signature of brown-colored ash-laden clouds emanating from a volcano.
AIRS Near Real Time BT_diff_SO2 dataset
Specific brightness temperature differences between BT(1361.44 cm-1) - BT(1433.06 cm-1) can be shown,
which can indicate SO2 gas emissions from volcanoes (NASA GES DISC, 2009). As implemented on the web
map, a legend graphic showing the BT_diff_S02 scale is automatically overlayed onto the top left-hand corner
of the map when this layer is turned on.
Figure 9 and Figure 10 below show examples of these datasets implemented on the web map. They
depict an early April 2009 eruption episode of the Redoubt volcano located in Alaska.
Figure 9 – AIRS False Color (infrared) image of volcanic ash (VA) cloud emissions drifting south from the
Redoubt volcano
P a g e 13 | Matt Stuemky
Figure 10 – AIRS BT_diff SO2 image showing SO2 gas emissions drifting to the southeast of the Redoubt
volcano
Ozone Monitoring Instrument (OMI): SO2, NO2, BrO, aerosols, ozone
As part of the NASA EOS program, the Aura satellite was launched into Earth orbit in July 2004. On
board is the Ozone Monitoring Instrument (OMI) which is capable of measuring numerous air quality
components including sodium dioxide (SO2), nitrogen dioxide (NO2), bromine monoxide (BrO) and aerosol
sources (smoke, dust, and sulfates). OMI can also measure ozone concentrations, in part by measuring cloud
coverage and air pressure at different levels of the troposphere. OMI is particular well-suited for monitoring
volcanic gas emissions, with its ability to measure the SO2 levels (in metric tons) in the lowest 5 kilometers
(approximately 3 miles) of the atmosphere. (NASA GES DISC, 2009)
Krueger (2006) indicates that NASA and NOAA scientists as well as numerous other researchers
worldwide are making use of OMI data for volcano related monitoring and research. It was determined that
although technically available to the public, most near real-time OMI datasets are not currently available in a
spatially-referenced format and delivery mechanism (i.e. WMS) for convenient incorporation into a web GIS.
P a g e 14 | Matt Stuemky
Although OMI data was not implemented at this time, it is worth noting that NOAA’s National
Environmental Satellite, Data, and Information Service (NESDIS) operates an experimental web-based service
using near-real time OMI SO2 imagery (http://satepsanone.nesdis.noaa.gov/pub/OMI/OMISO2/index.html). The
plan is to eventually incorporate near real-time OMI data into the Volcanoes of the World web map, as
additional layers for volcano monitoring, once they are more readily available from a WMS resource.
MODIS instrument: Aerosols
Tiny solid and liquid particles suspended in the atmosphere are called aerosols. Volcanic ash (VA) is
one significant example of atmospheric aerosol. The MODIS instruments on board the Terra satellite
(launched in 1999) and Aqua satellite (launched in 2002) are capable of measuring volcanic aerosols as well as
numerous other sources of atmospheric aerosols. Some of this remotely-sensed aerosol data is compiled into
an atmospheric indicator called the aerosol optical thickness (AOT) index. (NASA GES DISC, 2009) NASA
operates a WMS server that makes AOT raster imagery available. Since the more comprehensive OMI
datasets were not available for easy implementation, and given the time constraints of this project, the MODIS
AOT data was instead selected for implementation as an atmospheric indicator layer for the web map. Figure
11 below shows an example of this implementation of MODIS AOT imagery on the web map.
Figure 11 – MODIS AOT image showing volcanic ash (VA) / aerosol gas emissions from the Fuego volcano
located in Guatemala
P a g e 15 | Matt Stuemky
2. Ground level thermal (hot spot) indicators
Infrared imaging capabilities provided by the MODIS instruments on board the Terra and Aqua satellites
provide the ability to reveal thermal (hot spot) activity on the ground. One major application of this is by the
United States Forest Service and other natural resource agencies around the globe who use MODIS infrared
data for wildfire detection and monitoring. The infrared technology also lends itself to identifying other
thermal events on the surface of the earth, including volcanic eruptions.
MODVOLC
Scientists at the University of Hawaii’s Institute of Geophysics and Planetology (HIGP) have developed an
automated system which maps the global distribution of thermal hot spots in near real-time. Using unique
filter methods and algorithms, the system is designed to detect the signature of volcanic eruptions, although
large wildfires too are regularly detected by the system (HIGP, 2009). The primary objective of the MODIS
Thermal Alert System, or MODVOLC, is to allow scientists to detect volcanic activity anywhere in the world
within hours of its occurrence (Schmidt, 2004). Precise latitude and longitude values for each hot spot are
obtained, processed, and stored into the MODVOLC system. The posting of the locations of volcanic thermal
activity by MODVOLC is generally less than 24 hours after data acquisition (Davies, et al., 2008). This near realtime data is incorporated into a web map on the HIGP MODVOLC website.
HIGP provides a publically-accessible, fixed-length, space-delimited ASCII text file that is updated
continuously as the MODIS data is ingested into and processed by the MODVOLC system. This text file is
implemented into the Volcanoes of the World web map. As soon as the user selects the MODVOLC layer
option from the Monitoring menu, the most current version of the file is downloaded directly from the HIGP
web server using the Google Maps API. It is then processed using JavaScript and displayed as small red marker
points on the web map as shown in Figure 12 below.
Figure 12 – MODVOLC hot spots on the Fernandina volcano located in the Galápagos Islands
P a g e 16 | Matt Stuemky
3. Volcano webcams
A dataset containing information on live webcam images of volcanoes was created as the final volcano
monitoring layer for the web map. As soon as the user selects the Volcano webcams layer from the
Monitoring menu, a local XML file is loaded and parsed, placing webcam marker icons on the map in their
respective locations. Once the layer is loaded, any webcam image can be displayed simply by clicking the
webcam marker icon on the map. The layer is particularly useful for monitoring volcanoes that are currently
erupting, especially those volcanoes that have more than one webcam pointed at it. For example, the
Redoubt volcano currently has two different webcams pointed at it, both maintained by the Alaska Volcano
Observatory.
The webcams dataset was manually created for this project. It is a small XML file containing multiple
records, one for each webcam. Attributes include volcano name, location description of the volcano (country
and/or region), location description of the webcam, and point coordinates (latitude and longitude) of the
webcam. The file is stored in a folder called data, located on the same server where the web map application
resides. Due to time constraints, only a small collection of operating volcano webcams were identified and
added to the XML file. Over time, more will be added. Figure 13 below shows an example of an image from
one of the geo-referenced volcano webcams displayed on the Volcanoes of the World web map.
Figure 13 – Image from a volcano webcam located inside the crater of White Island, New Zealand
P a g e 17 | Matt Stuemky
Implementation: Historical Activity
Current Status and Monitoring are designed to be the most commonly used features on the Volcanoes
of the World web map because they are focused on keeping track of both new and ongoing volcanic activity.
However, incorporating some type of historical volcanic activity information is essential, especially for a web
GIS that depicts natural hazards. Dunbar (2007) mentions the importance of having easy access to natural
hazard information stored in long-term databases. These can be used to establish the past record of natural
hazard event occurrences. Such databases can be used to educate the public about natural disaster hot spots
around the globe and to help better understand overall trends with natural hazards.
National Geophysical Data Center (NGDC) – Significant Volcanic Eruptions database
The National Geophysical Data Center, a part of NOAA, regularly acquires, processes, and analyzes
data on earthquakes, tsunamis, and volcanoes worldwide. They have established separate databases for each
type of natural hazard (NGDC, 2009). Dunbar (2007) discusses the role of new web technologies, ones which
allow interactive search and retrieval capabilities in order to simplify access to natural hazard databases such
as the ones maintained by the NGDC.
The NGDC assimilates historical volcano data from the Smithsonian Institution Global Volcanism
Program and other organizations for their Significant Volcanic Eruptions database. The database contains
records covering a period from approximately 4350 BC to present day. The database is updated annually and
currently contains information on nearly 500 significant eruptions. All records are of volcanic eruptions that
resulted in deaths, property damage, and/or generated a tsunami (Dunbar, 2007). The NGDC uses this and
other natural hazards databases for their own web GIS application. However, the NGDC also furnishes a KML
file for general public use, one that contains the exact same information contained in their Significant Volcanic
Eruptions database.
For implementation into the Volcanoes of the World web map, a copy of the NGDC’s Significant
Volcano Eruptions KML file was obtained. In contrast with the “live data” downloaded from web servers
operated by the USGS Volcano Hazards Program, Volcanic Ash Advisory Centers and Smithsonian Global
Volcanism Program, the KML file from the NGDC is stored in a local folder called data, located on the same
server where the web map application resides. It should be noted that some minor modifications were made
to the KML file, to allow all hyperlinks for additional information to automatically open in a separate window
when clicked by the user rather than navigating away from the Volcanoes of the World web page. Aside from
that, the data is exactly the same as what is contained in the volcanoes database maintained by the NGDC.
P a g e 18 | Matt Stuemky
Figure 14 below shows how the volcanic eruptions data from the NGDC was implemented into the
Historical Activity menu of the Volcanoes of the World web map application. Selectable layers under the
Historical Activity menu allow the user to display one or more sets of volcanic eruption history. Five different
layers are available, each based on a specific date range. For each record inside the KML file, a reference to a
color triangle-shaped marker icon is used. These color-coded icons match exactly the symbols used by the
NGDC in their volcanoes database. The color indicates the overall severity of a volcanic eruption.
Figure 14 – Historical Activity menu
Figure 15 below shows an implementation example of historical eruption activity on the web map.
This example supports in part Dunbar’s (2007) idea of helping to educate the public about understanding the
location of natural disaster hotspots, in this case, volcano hazards. Specifically, depicting both current and
historical volcano activity features together on the web map can be rather eye-opening. Volcanic hot spots
become immediately apparent and can give the user some indication where the highest risk areas are located.
Figure 15 – Indonesia region showing several significant volcanic eruptions of varying severity since 1950 AD
P a g e 19 | Matt Stuemky
Implementation: Volcano Catalog
The fourth major implementation of the Volcanoes of the World web map application was to develop
the Volcano Catalog. The primary objective for developing this feature was to provide a volcano search
function that was easy to use and to have the search results be integrated directly into the web map interface.
The catalog is essentially a relational database table containing over 1500 records of volcanoes located around
the globe. While approximately 1500 potentially active volcanoes exist worldwide, on average about 500 of
these are active at any given time (Schmidt, 2004). The volcano catalog provides a way to quickly locate on
the map and to read a brief summary on any of these volcanoes, whether they are currently active or not.
Using standard database query procedures, the catalog can be used to search for volcanoes by name,
geographic location, and/or type (cinder cone, shield volcano, stratovolcano, etc.). Search results will be
processed and automatically pinpoint volcano locations directly on the web map using a unique marker icon.
Smithsonian Institution Global Volcanism Program
The Smithsonian Institution Global Volcanism Program maintains a database of over 1500 Holocene
era volcanoes. These are volcanoes that have been active at some time in the past 12,000 years. Each
volcano is given a unique volcano identification number (or VNUM), an identifier which is recognized
internationally for each documented Holocene era volcano located around the world. (Smithsonian GVP,
2009) On the Smithsonian GVP website, a section titled “Volcanoes of the World” provides an interface to
view information on all known and inferred Holocene volcanoes. Information available for each volcano
includes location, elevation, eruption chronologies and geological characteristics. Images of most of the
volcanoes are also available. (Guffanti, 2007) A subset of summary information is what forms the basis for
the Volcano Catalog that was developed and implemented for the Volcanoes of the World web map.
The Smithsonian Institution GVP makes available to the general public all their Holocene era volcano
data. This data is used on the GVP website but is also made freely available with downloadable files, including
a KML file for use in the Google Earth application and an Excel spreadsheet file. The Excel spreadsheet
contains summary information on each of the over 1500 volcanoes in the GVP master database.
One of the chief shortcomings of the GVP volcano information isn’t the content but, rather, how it’s
accessed and displayed. For example, to locate a volcano or volcanoes on the GVP website, the user must use
a standard search page to query by name or location. It works well but the search function and search results
are not integrated directly with the web maps used on the GVP website.
P a g e 20 | Matt Stuemky
MySQL database, PHP scripts, XML parsing
A MySQL database called gis_75487 had previously been created and configured on the production
web server used for this project. A new table was created in this database, to be used for the Volcanoes of the
World web map. To administer a MySQL database, a free set of downloadable client software tools are
available on the MySQL product website. However, a variety of alternative database management software
products are also available. One of the more popular ones is Navicat for MySQL which was used for all
database management tasks for this project.
Using the Navicat software, a new table called volcano_catalog was created in the gis_75487 database.
Fields were then manually added to the table corresponding to the column headers in the Excel file obtained
from the Smithsonian Institution GVP website. Once the table definition was created, Navicat's built-in import
wizard tool was used to populate the volcano_catalog table, using the specific option to load data from an
Excel file. Figure 16 below shows the end result of the import process, with 1535 records loaded.
Figure 16 – MySQL database table named volcano_catalog populated with data imported from an Excel file
obtained from the Smithsonian Institution GVP website
Various implementation approaches are available to get data from a relational database to integrate
with a Google Maps based web map application. However, the steps outlined in a technical document on
MySQL and Google Maps written by Fox (2007) were used, with some minor variations, for the Volcanoes of
the World web map. Using Fox's technique, the basic steps included using server-side PHP code to connect to
the MySQL database and perform a query and output the results into to an in-memory XML formatted data
stream. Finally, using Google Maps API functions and JavaScript code, the XML data was parsed and marker
icons were placed on the map canvas, similar to other implementation techniques used on the Volcanoes of
the World web map for handling point-based features.
P a g e 21 | Matt Stuemky
Volcano Catalog search options, Google- like word suggest feature
Figure 17 below shows a screenshot of the Volcano Catalog menu as implemented in the Volcanoes of
the World web map. There are three search options available: Name, Location and Volcano Type. The Name
and Location search fields are text input fields. The Volcano Type is a dropdown list populated with fixed
values, only one which can be selected at a time. Any one or all three search fields can be used when
performing a query.
Also integrated in the Volcano Catalog search menu is a “word suggest” feature, which is designed to
allow the user to more easily find matches as soon as they begin typing letters in either the Name or Location
search fields. The functionality is very similar to a popular Google search integration feature found within the
Firefox web browser and some websites. The word suggest feature is handled in the background by using a
combination of client-side JavaScript and server-side PHP code to perform immediate queries in the MySQL
database based on what the user types, rather than waiting for the user to click the Search button. It should
be noted that although this implemented feature works, there is occasionally a performance issue because the
web server where the MySQL database resides can be slow. As a consequence, the results will sometimes not
display right away. Figure 17 below shows an example of the word suggest feature, based on the letters typed
in by the user in the Name search field. A list of matches automatically appears immediately below the search
field. The user can either select any one of the items from the list or continue typing in the search field.
Figure 17 – Volcano Catalog menu
P a g e 22 | Matt Stuemky
Figure 18 below shows an example of how search results from the Volcano Catalog are displayed on
the web map. As soon as the user clicks the Search button, data is fetched from the MySQL database using
the techniques described above (Fox, 2007). White-colored triangle marker icons representing each volcano
record retrieved from the query are placed onto the map canvas. Once all point markers have been loaded,
the map will automatically be repositioned to the location of the first marker that was added. A pop-up
information window for the first marker will automatically open, showing the summary information on the
volcano, including a photo if available. A hyperlink located at the bottom of the window, when clicked, will
automatically open a new tab or browser window and navigate to the volcano’s detailed information page on
the Smithsonian Institution Global Volcanism Program website.
Figure 18 – Volcano Catalog record shown on the web map with a pop-up information window displaying
summary information and a photo of the Arenal volcano located in Costa Rica
P a g e 23 | Matt Stuemky
Implementation: Other Layers
The final implementation phase of the Volcanoes of the World web map application involved
conducting additional research to identify other spatially-enabled datasets that would enhance the web map
features already implemented, in order to provide a more complete web GIS. Ideally, these would be items
that could be easily incorporated as additional map layers without a lot of extra time and effort involved,
considering the time constraints of the project. Figure 19 below shows the Other Layers menu with the
various options that are currently available.
Figure 19 – Other Layers menu
U.S. Geological Survey Earthquake Hazards Program: Earthquakes and Tectonic plate boundaries
The U.S. Geological Survey Earthquake Hazards Program (EHP) provides several spatially-enabled
datasets in a GeoRSS-based XML format, suitable for easy implementation into a web GIS. (USGS EHP, 2009)
The following EHP data sources were selected for implementation into the web map:
Earthquakes – past week
Tectonic plate boundaries / major fault lines
As implemented, locations of earthquake events from the past week are available as a map layer, using
a threshold of either Magnitude 5.0+ or Magnitude 2.5+. Magnitude strength of each earthquake event
shown on the web map is represented by colored-coded markers as shown in Figure 20 below. This layer is
most useful when zoomed in to a seismically active region (i.e. Alaska) where numerous earthquake markers
will typically be displayed on the map. Identifying recent earthquakes in the vicinity of a currently active
volcano can be useful for analysis. Turning on the layer depicting tectonic plate boundaries and major fault
lines provides some additional insight by showing their proximity to recent earthquakes and active volcanoes.
P a g e 24 | Matt Stuemky
Figure 20 – Earthquake events of different magnitude located in the Aleutian Islands region of Alaska
Volcano Live – volcano activity news by John Seach
John Seach is an adventure traveler who specializes in studying volcanoes up close. He has worked on
many television documentaries chronicling his travel and volcano explorations. John Seach is the founder of
Volcano Live, a news and adventure travel website devoted to information on volcanoes around the world.
His website provides an RSS news feed on recent volcano activity. (Volcano Live, John Seach, 2009) The RSS
news feed was selected for implementation into the web map. Implementation was accomplished in part by
using an RSS to GeoRSS conversion process as described in the Testing and Technical Issues section below.
Thematic maps
Datasets suitable for use as special thematic map types (base map layers) were selected from the
OnEarth project, part of NASA’s Jet Propulsion Laboratory, and from Columbia University’s Socioeconomic
Data and Applications Center (SEDAC) and the Center for International Earth Science Information Network
(CIESIN). To implement these custom map types for the Volcanoes of the World web map, WMS servers
operated by NASA JPL OnEarth and SEDAC/CIESIN were used to retrieve the following tiled raster imagery:
Blue Marble “Next Generation”
Population Density
Natural Disaster Hotspots (Seismic Hazards)
P a g e 25 | Matt Stuemky
These datasets do not display real-time features like the satellite-based imagery used for volcano
monitoring do. However, they do enhance the web map beyond the standard map types available within the
Google Maps API, to provide options for performing additional spatial analysis.
Blue Marble “Next Generation” is a 500-meter true color earth dataset enhanced with shading of both
land topography and ocean bathymetry. It is designed to offer a realistic view of the earth’s surface without
any clouds obscuring surface features. Imagery is derived from the MODIS Terra satellite. Twelve different
Blue Marble datasets corresponding to each month of the year are available from the OnEarth WMS server,
each depicting different seasonal dynamics. For example, a Blue Marble dataset for the month of January
shows a more pronounced presence of snow in higher elevations of the northern hemisphere compared to a
Blue Marble dataset for the month of August. (NASA JPL OnEarth, 2009) The specific Blue Marble dataset
used for the Volcanoes of the World web map corresponds to the current month.
Population Density is a dataset from SEDAC that provides estimates of human population for the year
2010. It is but one of several global population datasets that SEDAC makes available for past and future years.
Natural Disaster Hotspots is a natural hazards dataset from SEDAC that is based on earthquake/seismic history
around the world. (Columbia University SEDAC CIESIN, 2009) The use of a seismic hazards dataset is useful
because earthquakes and volcanoes often occur in close proximity to each other, especially in areas where
tectonic plates are subducting under one another and/or major fault lines exist. A legend graphic is
automatically overlayed in the top left-hand corner of the map canvas whenever the Population Density and
Natural Disaster Hotspots thematic map layers are turned on.
Figure 21 – California region using each of the three thematic map types Blue Marble “Next Generation”,
Population Density and Natural Disaster Hotspots
P a g e 26 | Matt Stuemky
Testing & Technical Issues
This section briefly describes some testing scenarios that were used once the Volcanoes of the World
web map application was fully developed with all Current Status, Monitoring, Historical Activity, Volcano
Catalog, and Other Layers features available for use. The primary goal of final testing was to evaluate how
well the different datasets integrated together to form a complete web GIS, by using the different layers at the
same time to perform some basic spatial analyses. Also, several technical issues that arose during testing are
described below.
Testing example: analyzing a currently active volcano using various layers on the web map
Marker icons on the map representing volcanoes monitored by the USGS Volcano Hazards Program
offer the single best indicator for quickly identifying where the most current volcano activity is in the United
States and its territories. Indicators for Advisory/Yellow, Watch/Orange, or Warning/Red are easy to identify
on the map because the icons are larger and stand out more easily compared to those volcanoes with a
Normal or Unassigned status. For quickly identifying current volcanic activity for the rest of the world, the
VAAC Volcanic Ash Advisory marker icons on the map are the best ones to look for. Both the USGS VHP and
VAAC update their datasets several times a day.
If a particular volcano has been identified with a Current Status marker on the map, and the user
wishes to investigate further, the logical first task would be to zoom in the map over that location, click the
marker icon itself to display the pop-up information window, and read the summary information. Optionally,
the user may click the hyperlink at the bottom of the summary to open a new page in the web browser
showing more detailed information on the volcano.
Next, the user can go to the Monitoring menu and turn on, one by one, the various atmospheric
indicators layers to see if there is any evidence of volcanic ash (VA) clouds, water vapor/steam clouds, SO2, or
other emissions coming from the volcano. Since the output of volcano eruptions can vary greatly based on
geographic location, prevailing climate factors, current weather conditions (including normal meteorological
cloud cover), and geochemical makeup of the volcano itself, it should always be assumed that certain
atmospheric indicators may not always be present. However, a moderate to large eruption will almost always
show evidence of VA in some of the satellite imagery. Also, turning on the MODVOLC layer will often display
one or more red markers, indicating thermal hot spots, directly on or near a currently active volcano. One of
the main reasons for using the Monitoring feature of the Volcanoes of the World web map is to provide
P a g e 27 | Matt Stuemky
confirmation of new or ongoing activity as indicated by any Current Status information that is shown for a
particular volcano.
Using options under the Historical Activity menu, the user can determine if there are any records of
significant volcanic eruptions of a particular volcano, or if other nearby volcanoes had significant eruptions in
the past. The Volcano Catalog can also be useful when looking at a currently active volcano. The user can
type in the first few characters of the volcano name (“Redoubt”) or the location of the volcano (“Alaska”) and
then click the Search button to have a Volcano Catalog marker appear on the map and automatically display
summary information and a photo.
Turning on other layers such as earthquakes under the Other Layers menu and volcano webcams under
the Monitoring menu can provide the user with additional opportunities to evaluate the severity of a current
volcanic eruption. For example, numerous minor magnitude earthquakes have occurred in the vicinity of the
Redoubt volcano since March 2009 and weekly earthquake events feature prominently on the web map when
the layer is turned on. Viewing imagery provided by two different webcams maintained by the Alaska Volcano
Observatory that are currently pointed at Redoubt can also be quite interesting. In recent weeks, these two
webcams have occasionally shown very dramatic views of large volcanic ash clouds emanating from the top of
the mountain!
Figure 22 – Testing example: analyzing the currently active Redoubt volcano
P a g e 28 | Matt Stuemky
Testing example: Volcano Catalog
The Volcano Catalog is designed to be used to quickly search on volcanoes around the world. Not only
can the user search on volcanoes by Name or Location or Type they can also search using all three of these
parameters. One simple example that demonstrates the spatial accuracy of the Volcano Catalog data when
overlayed on the web map is to do a search by Location. This will identify on the map only those volcanoes
that exist within the border of a particular country or region. For example, as shown in Figure 23 below, when
using the Volcano Catalog, typing in “Costa Rica” in the Location text box and clicking the Search button will
place ten marker icons on the map. There are many other volcanoes located geographically nearby, just on
the other side of the border in Nicaragua, but only the Costa Rican volcanoes will be shown.
Figure 23 – Testing example: Volcano Catalog search for all volcanoes located within Costa Rica
Technical issue: Incorporating datasets from WMS sources using the Google Maps API
Using the Google Maps API objects GTileLayer and GMapType and JavaScript code, a series of custom
map types (base map layers), were created by retrieving tiled raster data from WMS resources. Some of these
base map layers, such as the MODIS Terra “Daily Planet” and AIRS, are used as atmospheric indicator options
for near real-time volcano monitoring. Other are implemented as special thematic maps, including the Blue
Marble “Next Generation”, Population Density and Natural Disaster Hotspots which were added as options
under the Other Layers menu.
As with the standard Google Maps API map types (Street Map, Satellite, Terrain), the custom map
layers automatically place fixed-size raster image tiles onto the map canvas as the user zooms in and out and
moves around the map. Testing revealed that these WMS-derived images were sometimes slow to load and
occasionally failed to load at all. The time of day and WMS server used often seemed to be factors in how
reliably the imagery would load onto the map. No viable solution to this intermittent problem was found.
P a g e 29 | Matt Stuemky
Technical issue: Limiting zoom levels on all custom map types
Testing revealed that tiled raster imagery retrieved from WMS sources did not generally offer a level of
resolution that was satisfactory once certain large-scale zoom levels were reached. The resolution of some
datasets was worse (i.e. AIRS False Color) than others (i.e. MODIS Terra Daily Planet). The solution was to
write a small function in JavaScript designed to manipulate the Google Maps API to limit zoom levels for each
of the different custom map types that were created for the Volcanoes of the World web map.
Technical issue: RSS to GeoRSS conversion
RSS data sources can be geo-referenced. Although various solutions exist to achieve this, a web-based
tool on the GeoNames website allows this conversion to be performed easily (GeoNames, 2009). Conversion
of the RSS data provided by the Smithsonian Institution GVP into GeoRSS format was required. A small PHP
script was created and configured to run as a scheduled task once a week (Wednesday evening) on the web
server where the Volcanoes of the World web map application resides. Its purpose is to fetch a copy of the
current Weekly Volcanic Activity Reports RSS feed directly from the Smithsonian GVP website and then
convert it into GeoRSS format using the GeoNames utility, and save it as a local file in a folder named data
located on the same server where the web map application resides. This same RSS to GeoRSS conversion
process was also applied to the Volcano Live RSS feed, except that the PHP script used for fetching the data is
configured as a scheduled task that runs every six hours instead of once a week.
Technical issue: use of “live data” and keeping the web map “current”
Many features displayed on the Volcanoes of the World web map use data that are updated frequently
by the organizations they are obtained from. Refer to Appendix A: Data Sources to view these update
frequencies (some are estimates). Data retrieved from the U.S. Geological Survey Volcano Hazards Program
and Earthquake Hazards Program, Volcanic Ash Advisory Centers, all NASA satellite imagery except Blue
Marble, MODVOLC, and Volcano Live are all considered “live data” sources. This is in contrast with other web
map features, such as Historical Activity which uses KML files stored in a local folder on the web server, and
the Volcano Catalog which uses data stored in a local MySQL database on the web server.
Two solutions have been implemented to keep the web map “current”. If the web map remains
displayed in a web browser continuously, the page will automatically reload every two hours. Additionally, the
user can manually refresh the web map at any time simply by clicking the
button. This will
restore the default map view, automatically reload the latest data from all Current Status layers, and reset all
other spatial layers that rely on live data so they will display the most current information when selected.
P a g e 30 | Matt Stuemky
Final Result
Volcanoes of the World web map application: http://gis.manyjourneys.com/volcanoes/
When the web map application first loads, the default map view is worldwide, positioned over the
Pacific Ring of Fire. This is the Pacific Ocean basin, a region on Earth where the largest numbers of volcanic
eruptions and earthquakes occur. The default map type used is the Google Maps hybrid map (satellite with
map labels). The default spatial layers shown are Current Status features representing the most recent alert
levels and status information issued by the U.S. Geological Survey Volcano Hazards Program, Volcanic Ash
Advisory Centers, and Smithsonian Institution Global Volcanism Program. To maintain a simple, clean user
interface, all features are organized into JavaScript-driven menus positioned at the top of the screen. The rest
of the screen is devoted to the map, which includes standard Google Maps controls for zoom, move, and map
type. The map canvas automatically fills the web browser window based on its current height and width.
Figure 24 – Volcanoes of the World web map application
P a g e 31 | Matt Stuemky
The Volcanoes of the World web map, as implemented for the class project, is intended to only be the
first phase of the application. Additional enhancements are planned. For example, the near real-time
monitoring feature was determined to be one of the most important implementations of the web map. One
of the next objectives is to enhance the monitoring feature further by incorporating some of the newest and
more comprehensive datasets derived from instruments on board NASA satellites, for example, OMI SO2,
once they are available from a WMS resource.
Long term, the plan is to use the Volcanoes of the World web map application as a foundation to build
a more comprehensive "geo hazards" web GIS used for monitoring a variety of geological natural hazards
including volcanoes, earthquakes, tsunamis, and landslides. This is in contrast with meteorological (weather)
type natural hazards such as tornadoes, thunderstorms, hurricanes/typhoons, floods, and wildfires which
already seem to be fairly well represented on the World Wide Web with well-designed interactive web map
applications.
P a g e 32 | Matt Stuemky
References
Davies A.G., et al. (2008). The Model-Based Volcano Sensor Web: Progress in 2007. Presented at the 2008 NASA Earth
Science Technology Conference - ESTC2008. Retrieved on April 6, 2009 from
http://esto.nasa.gov/conferences/estc2008/papers/Davies_Ashley_A7P3.pdf
Columbia University Socioeconomic Data and Applications Center, Center for International Earth Science Information
Network. (2009). Website: http://sedac.ciesin.columbia.edu/
Dunbar, P. (2007). Increasing public awareness of natural hazards via the Internet. Natural Hazards, 42: pp. 529-536.
Fox, Pamela, et al. (April 2007). Using PHP/MySQL with Google Maps. Retrieved on March 15, 2009 from
http://code.google.com/support/bin/answer.py?answer=65622&topic=11364&ctx=sibling
GeoNames.org. RSS to GeoRSS converter. (2009). Website: http://www.geonames.org/rss-to-georss-converter.html
Guffanti, M., et al. (2007). Technical-Information Products for a National Volcano Early Warning System. United States
Geological Survey: Open File Report 2007-1250. Retrieved on April 6, 2009 from
http://pubs.usgs.gov/of/2007/1250
Hawaii Institute of Geophysics and Planetology, MODVOLC. (2009). Website: http://modis.higp.hawaii.edu/
Keeping a wary eye on volcanoes. (2009, March 27). The Week Magazine, 9(405). Retrieved on April 6, 2009 from
http://www.theweek.com/article/index/94425/Keeping_a_wary_eye_on_volcanoes
Krueger, A. et al. (2006, October 3). NASA research satellite data for volcanic aviation hazards. Presented at the
Support to Aviation Control Service (SACS) workshop at Belgian Institute for Space Aeronomy. Retrieved on
April 6, 2009 from http://sacs.aeronomie.be/workshop/talks1/Krueger_NASA_Oct2006.ppt
National Aeronautics and Space Administration, Jet Propulsion Laboratory, OnEarth. (2009).
Website: http://onearth.jpl.nasa.gov/
National Aeronautics and Space Administration, Goddard Earth Sciences Data and Information Services Center. (2009).
Website: http://daac.gsfc.nasa.gov/
National Geophysical Data Center, Natural Hazards. (2009).
Website: http://www.ngdc.noaa.gov/hazard/
Peduzzi, P., Dao, H. and Herold, C. (2005). Mapping Disastrous Natural Hazards Using Global Datasets.
Natural Hazards, 35: pp. 265–289.
Schmidt, L.J. (2004). Sensing Remote Volcanoes. Website: http://earthobservatory.nasa.gov/Features/monvoc/
Smithsonian Institution Global Volcanism Program. (2009). Website: http://www.volcano.si.edu/
United States Geological Survey Earthquake Hazards Program. (2009). Website: http://earthquake.usgs.gov/
United States Geological Survey Volcano Hazards Program. (2009). Website: http://volcanoes.usgs.gov/
Volcano Live, John Seach. (2009). Website: http://www.volcanolive.com/
P a g e 33 | Matt Stuemky
Appendix A: Data Sources
Organization / Reference URL / Dataset description
Source format – type
Update frequency
NASA - Near Earth Observing (NEO) system / Goddard Earth Sciences Data and
Information Services Center (GES DISC)
http://disc.sci.gsfc.nasa.gov/
AIRS false color/RGB - indicator of volcanic SO2 emissions and volcanic clouds,
AIRS infrared BT_diff_SO2 - indicator of volcanic SO2 emissions
MODIS aerosol optical thickness - primarily an indicator of volcanic ash
WMS – tiled raster (png)
WMS – tiled raster (png)
WMS – tiled raster (png)
Every 6-24 hours
Every 6-24 hours
Every 12-24 hours
NASA – Near Earth Observing (NEO) system / JPL OnEarth
http://onearth.jpl.nasa.gov/
Daily Planet – visual view of the Earth showing current cloud coverage
Blue Marble – MODIS-derived true color dataset showing seasonal dynamics
WMS – tiled raster (jpeg)
WMS – tiled raster (jpeg)
Every 6-24 hours
Annually
Columbia University – Socioeconomic Data and Applications Center (SEDAC),
Center for International Earth Science Information Network (CIESIN)
http://sedac.ciesin.columbia.edu/mapserver/
Population Density – datasets available for 1990, 2000, 2005, 2010, 2015
Natural Disaster Hotspots – dataset on Seismic Activity/Volcanic Hazard zones
WMS – tiled raster (png)
WMS – tiled raster (png)
Undetermined
Undetermined
U.S. Geological Survey - Volcano Hazards Program (VHP)
http://volcanoes.usgs.gov/
Current Status (primary) – status of most actively monitored volcanoes
Current Status (other) – status of other volcanoes in U.S. and its territories
XML – point
XML – point
1-2 times daily
1-2 times daily
Smithsonian Institution – Global Volcanism Program (GVP)
http://www.volcano.si.edu/
Current Status – weekly reports of new/ongoing volcanic activity worldwide
Summary info on 1500+ Holocene era volcanoes worldwide
RSS (to GeoRSS) – point
Excel (XLS) / KML
Once a week (Wed PM)
Undetermined
Volcanic Ash Advisory Centers (VAAC)
http://www.ssd.noaa.gov/VAAC/washington.html
Current Status – reports of current Volcanic Ash Advisories
KML – point
Every 30 minutes
ASCII TEXT – point
Every 12-24 hours
National Geophysical Data Center (NGDC)
http://www.ngdc.noaa.gov/hazard/hazards.shtml
Significant Volcanic Eruptions – 400+ eruptions from 4350 BC to Present
KML - point
Annually
U.S. Geological Survey - Earthquake Hazards Program
http://earthquake.usgs.gov/
Earthquakes – past 7 days worldwide, magnitude 5.0+ and magnitude 2.5+
Tectonic plate boundaries and major fault lines
XML – point
KML – polyline
Every 5-30 minutes
Infrequently
Volcano Live – John Seach
http://www.volcanolive.com/
News on recent volcanic eruptions
RSS (to GeoRSS) – point
1-2 times daily
Volcano webcams - manually created dataset
Approximately 25 geo-referenced webcams pointed at volcanoes
XML – point
Varies by webcam
Hawaii Institute of Geophysics and Planetology – MODVOLC
http://modis.higp.hawaii.edu/
Ground level thermal (hot spots) worldwide - used for possible indicators of
volcanic activity
P a g e 34 | Matt Stuemky