Download Bolivia Seismicity and Networks

Bolivia Networks and Seismicity
Gonzalo Fernández
Observatorio San Calixto, La Paz - Bolivia.
Email:[email protected]
Introduction.The Observatorio San Calixto is a nonprofit institution that executed the seismic and
infrasound monitoring around Bolivia, during 102 years there is not any day without
submitting a seismic bulletin. Bolivia hosts three IMS station, one primary seismic station
PS06, one auxiliary seismic station AS08 and one infrasound station IS08 which are operated
by Observatorio San Calixto thus we are the National Data Center.
Brief Description of National Seismic Network.Our seismic network around LPAZ have four seismic short period vertical component
stations which work with the French (CEA/DASE) cooperation, in addition the infrasound
station IS08 is also under the French cooperation. At Bolivian oriental part is located the
AS08 seismic station which runs three short period sensors (Z, N-S, E-O) and three long
period sensors (Z, N-S, E-O) at the Bolivian south part the station MOC runs three short
period sensor (Z, N-S, E-O). Both stations are under the French cooperation (CEA/DASE).
LPAZ station has one broad band three component sensor and one short period one
component sensor, this station works with the US (AFTAC) cooperation.
Unfortunate our new digital seismic network does not work because of cooperation problems
with a Telecom company, it worked from 2011 to 2013, the low collaboration with the
telecom company forced us to stop the project stopping the work of 18 seismic stations.
Seismic Stations
Station Name
Station Code
Latitude
Banderani
BBOB
-16.141829
Longitude Elevation Installed since
-68.132467
3911
1975
Gloria
BBOD
-16.637430
-68.598088
4235
1983
Chanca
BBOE
-16.812908
-67.983326
4325
1982
Jacaque
BBOJ
-16.975080
-68.191520
4125
2008
LPAZ
PS06
-16.2844
-68.1289
4810
-16.2844
-68.1287
4810
1993
OSC
BS00
-16.49394
-68.13437
3640
2015
San Ignacio
AS08
-15.9877
-61.0703
520
1988
Mochara
MOC
-21.2542
-65.6394
3580
1985
Type of Instrument
Network Transmision Type
ZM - 500 short period sensor
OSC
vertical component
ZM - 500 short period sensor
OSC
vertical component
Telemetric - Analog
ZM - 500 short period sensor
OSC
vertical component
ZM - 500 short period sensor
OSC
vertical component
KS54000 - three components
Broad Band borehole sensor
OSC
Telemetric - Digital
GS-21 one component borehole sensor
Short period three component
OSC
IP
station
ZM-500 short period sensor
OSC
vertical component
ZM-500 short period sensor
OSC
East - West component
ZM-500 short period sensor
OSC
North - South component
VSAT - VPN MPLS
LM-500 Long Period Vertical Component OSC
LM-500 Long Period East - West
OSC
Component
LM-500 Long Period North - South
OSC
Component
ZM-500 short period sensor
OSC
vertical component
ZM-500 short period sensor
OSC VSAT - VPN MPLS
East - West component
ZM-500 short period sensor
OSC
North - South component
Infrasound Stations
Station Name
Peñas
Station Code
Latitude
IS08 H1
-16.215297
Longitude Elevation Installed since
-68.453478
4042
IS08 H2
-16.202448
-68.456145
4032
IS08 H3
-16.217554
-68.442927
4071
IS08 H4
-16.221751
-68.463800
4017
1998
Type of Instrument
MB2000 Microbarometer
Table 1. Main Characteristic of our seismic Network.
Figure 1. Seismic Network in Bolivia.
Network Transmision Type
OSC
Telemetric - Digital
Bolivian Seismicity.The Bolivian seismic activity is characteristic for the dynamic and cinematic process in internal
earth, where the seismicity is originated as:
Sesimogenic Sources according the origin:
-
-
-
The seismogenic sources in the Crust associated to the continental deformation: For
this kind of sources the earthquakes considered have the depth lower than 75Km, this
depth belongs to Bolivian crust thickness.
Sub – Source related to the potentially active faults that has generated seismicity:
Probably in the Holocen age (quaternary period), their evidences can be seen around the
surface and can be identified due the geologic features, geomorphologic and structural
presents in the current sediments, also the characterization can be obtained with the
Geodesy and Pale seismicity, they will allow us to know the kind of fault, the moving
average, the shift length, the likely magnitude and the return period, which can be
hundreds of years or thousands of years (Brooks et al 2010, Ramírez, et al 2009).
Sub Source with seismicity in different crustal plates: generally located to depths greater
than 5Km, they are frequently and the magnitudes are lower than the last one, this kind
of earthquakes happens around Cochabamba department
Seismogenics Sources related to the Subduction Process:
The earthquakes from this seismogenics source are located inside the Nazca Plate, they are
originated due the subduction process, the earthquake activity at this seismogenic source is
not continuously because there are not earthquakes between 500Km to 700Km depth, the
main characteristic is the distribution in depth from 100km to 700Km, and the subductions
earthquakes have two different sources:
-
-
Sub Seismogenic Source located between a depth from 100km to 350Km: Also known
as intermediate earthquake, the occurrence frequency is greatest than the subduction
earthquakes, we can find them around La Paz (south west), Oruro and Potosi
Department.
The sub subduction source for earthquakes that happens at depths between 500Km to
700K:, Known as depth earthquakes, the main characteristic is that they do not happen
all the time but they can generate a big magnitude earthquake, as an example, the
earthquake of 09-06-1994 a 8 Mw Magnitude, it happened under 635Km of
Rurrenabaque, Beni department, the occurrence is under La Paz (north), Santa Cruz and
Tarija Departments..
Far Away Sources:
This kind of seismogenic source is located at the contact zone between two plates, Nazca and
South America, the depth is between 20Km to 50Km. The earthquakes happen as mainly
result due Nazca and South America rubbing and friction (the subduction process). The
second origins belongs to the subduction earthquakes with depths from 75Km to 200Km.
The following maps shows the earthquakes with magnitude above 6 from 1960 and
magnitude above 4 since 1994.
Figure 2. Seismicity in Bolivia since 1960 with Magnitudes higher than 6.
Figure 3. Seismicity in Bolivia since 1994 with Magnitudes higher than 4.