Download Is There An Earthquake Migration Global Pattern?

Is There An Earthquake
Migration Global Pattern?
S13A-2516
UnB
Aroldo M. M. dos Santos², George S. França¹, André G. da Silveira², Gregorio V. Frigeri², Giuliano S. Marotta¹
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
¹ Grupo de Pesquisar Sismicidade Induzida e Natural/CNPq Observatório Sismológico - Universidade de Brasília
² Universidade de Cuiabá
Abstract
Earthquake migration patterns before large earthquake
were proposed by Mogi, (1968). The existence of the correlation between earthquakes over distances that show
probable global interdependence is a theme that is certainly one of the most intriguing in field of seismology.
In this job, we will present the phenomenology of earthquake migration global seismic pattern empirically, in order to ensure statistically the correlation of long range and
lead to confrontation these seismic patterns. We used the
USGS catalog. We found that the pair of events that have
a good correlation are confirmed statistically.
As Shebalin (1996) shown the earthquake chain, we show
that first stage of the earthquake prediction correlation
for large distances.
Introduction
Earthquake migration patterns before large earthquake
were proposed by Mogi (1968) and the existence of the correlation between earthquakes over distances show probable global interdependence (Romanowicz 1993, Shebalin
2006). Others studies of spatio-temporal changes in seismicity prior to large earthquakes (Gutenberg and Richter, 1954; Keilis-Borok and Malinovskaya, 1964; Prozorov
and Schreider, 1990; Shaw et al., 1997; Jaume and Sykes,
1999; Keilis-Borok, 2003, Wu et al., 2008) also show the
evidences of long-range correlation to large earthquakes.
This theme is certainly one of the most intriguing in field
of seismology, and might explain this probable correlation and identify the patterns earlier proposed.
Objective
We intended to prove the hypothesis that earthquakes and
seismic migration may be related to different points in
long distances around the world MOGI (1968). From this
point the seismic migration patterns could be identified,
allowing it’s identification before the major earthquakes
occur. One can also identify the existence of correlation
between these earthquakes over distances, showing probable global interdependence.
Earthquake Migration
Global Pattern
We consider the earthquake migration patterns, pairs of
events with similar magnitudes and time variation, considering only the main events without using the presence
of aftershocks. After selecting the patterns, we established
linear correlations between migration events based on observation of time, epicenter, depth and magnitude.
Identifying the Earthquake
Migration Global Pattern
We used the data from the catalogs covering a time period from 1998 to 2011 and selected four seismic patterns
that had almost constants and similar magnitudes. Each
Seismic pattern was named according to a Flinn-Engdahl
Region (Flinn et al., 1974). For this work we present the
migrations (Figure 1) of Vanuatu-North Japan, Fiji-Peru,
Bolivia-Xizang and Santiago-Tonga.
Migration 4 - Santiago Del Estero to Tonga [Flinn and
Engdahl regions - Santiago Del Estero, 132 - Santiago Del
Estero Prov., Arg., Tonga,171 - South Of Fiji Islands, 173
Tonga Islands and 174 Tonga Islands Region].
1
2
Parameters and Correlations
3
To define the precision of the selected seismic patterns we
defined mathematical models to establish a linear correlation for seismic events pairs based on observations of time
(T1 e T2), epicenter [P1(l1,j1) and P2(l2,j1)], depth(h1
and h2) and magnitude (M1 and M2). Thus, were defined
as parameters to be determined the variations between
distance of epicenter, magnitude, and travel time between
the events (ΔT, ΔM and ΔD).
T2 = T1 + ΔT (01)
P2 = P1 + ΔD (02)
M2 = M1 + ΔM (03)
Assuming that the parameters are independent of each
other, we used the mean and standard deviation as statistical information for the pair events, and as criteria for
selecting event pairs automatically we used the standard
deviation as the threshold of the selected data.
4
Xizang
Bolívia
Bolívia
Xizang
Fiji - Peru
Fiji171
to Peru
Fiji 181
to Peru
Vanuatu
Japan
Santiago
Tonga
Distances
Visual (º)
Distances
Visual (º)
Difference
of magnitudes
Visual
15
171
1.07±0.16
2.53±2.18
162.32±1.49
155.69±4.09
0.03±0.15
-0.02±0.30
7
157
0.68±0.15
2.31±2.05
160.65±1.03
155.57±4.03
0.03±0.13
0.02±0.31
44
0.28±0.07
103.26±0.81
0.08±0.06
255
0.41±0.33
98.08±1.41
0.02±0.30
411
0.32±0.27
98.66±1.31
0.05±0.30
49
625
0.20±0.05
0.48±0.47
59.24±1.29
59.06±1.67
-0.20±0.06
-0.18±0.30
5
24
20.64±9.61 0.42±0.47
112.69±4.47
99.32±1.67
-0.50±0.430
-0.13±0.40
8
0.61±0.48
98.65±1.44
-0.16±0.18
Manually collected data is used as the basis for automation and consolidation of probable seismic migration using the
Flinn-Engdahl region as accurately as possible. It was observed that the pairs of consequent events over magnitude are
well correlated. Only migration 4, manually collected, showed inconsistency with the value obtained automatically, however it was still possible to observe a probable migration pattern. The data collection showed that the migration path 1
has forward and reverse, with automated values greater than the average collected manually, one for the direct path with
an average travel time of 2.5 days and 2.3 for the reverse path. The other migrations demonstrated values below 0.6 days
(~ 14 hours), it can be directly correlated with the distance of migration. Migration 2 was separated, as they are in different regions Flinn-Engdahl, however did not show big difference. Migration 3 remained with the manual collection
and migration 4, was separated according to depth, with a low number of observations, but we can infer that the travel
time is greater for those depths. Graphs were made Ncum (cumulative number of earthquake the day versus days), emphasizing the probability of migration patterns. The next step is to test the correlation between various parameters to
ensure the migration of real events and set more migration paths.
Results
There were two processes, the first by visual observation
(manual) where pairs of events from the catalogue (from
2004-2011) were selected, and the second was through the
same catalogue, but with automatically selected pairs of
events, considering only the first subsequent event (1998
to 2011), and then determining the parameters (Table 1).
In this work we separated four migration patterns:
Migration 1 - Xizang to Bolivia [Flinn and Engdahl regions
- Xizang, 305 (Western Xizang-India Border Region) and
306 (Xizang), Bolivia, 124 (Chile-Bolivia border region)
and 125 (Southern Bolivia)].
Migration 2 - Fiji to Peru [Flinn and Engdahl regions - Fiji,
171 – South of Fiji Islands and 181 - Fiji Islands Region,
Peru, 108 - Off Coast Of Northern Peru, 109 - Near Coast
Of Northern Peru, 110 - Peru-Ecuador Border Region,
111 Northern Peru, 112 Peru-Brazil Border Region, 113
Western Brazil, 114 Off Coast Of Peru, 115 Near Coast
Of Peru, 116 Central Peru, and 117 Southern Peru].
Migration 3 - Vanuatu to Japan [Flinn and Engdahl regions - Vanuatu, 185 Vanuatu Islands Region and 186
Vanuatu Islands, Japan, 226 Near West Coast Of Honshu, 227 Eastern Honshu, 228 Near East Coast Of Honshu, 229 Off East Coast Of Honshu and 230 Near S. Coast
Of Honshu].
N
Seismic
Pattern
Travel time Travel time
Obs. Obs.
Visual
Aut. (days)
Visual Aut.
(days)
Difference
of magnitudes
Aut.
Conclusion
References
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Bulletin of the Seismological Society of America, vol. 64, p. 771-993.
Gutenberg, B., Richter, C.F., 1954. Seismicity of the Earth and Associated Phenomena. Hafner, New York.
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moment/energy release prior to large and great earthquakes. Pure Appl. Geophys. 155, 279–306.
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Prediction. Springer- Verlag, Berlin Heidelberg, pp. 1–36.
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earthquakes. J. Geophys. Res. 69, 3019–3024.
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Earthquake Res. Inst. Univ. Tokyo, 46, 1103– 1125.
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a tool for mid-term earthquake prediction in southern California. Pure Appl. Geophys. 133,329–
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Science 260, 1923–1926.
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Shebalin P., 2006. Increased correlation range of seismicity before large events manifested by
earthquake chains. Tectonophysics, 424, 335– 349, doi:10.1016/j.tecto.2006.03.040.
Young, J.B., Presgrave, B.W., Aichele, H., Wiens, D.A. and Flinn, E.A., 1996, The Flinn-Engdahl Regionalisation Scheme: the 1995 revision, Physics of the Earth and Planetary Interiors, v.
96, p. 223-297.
Wu Yi-Hsuan, Chien-chih Chen, and John B. Rundle, 2008, Detecting precursory earthquake
migration patterns using the pattern informatics method. Geophysical Research Letters, V 35,
L19304, doi:10.1029/2008GL035215.
The study of earthquakes forecasting/prediction seemed to be a path without solution, bringing several attempts to
find consistent predictions, such as the precursors of major events, which seemed to be just a regional solution without demonstrating a global effect correlation. Recently, a new methodology has been identified in earthquake forecast,
crediting a new step for seismology. Thus, this work aims to a new understanding of the behavior of earthquakes based
on empirical observation of seismic catalogues of the leading world seismology centers such as European Mediterranean Seismological Centre (EMSC), National Earthquake Information Center – United Stated Geological Survey (NEIC-USGS), Incorporated Research Institutions for Seismology (IRIS), German Research Centre for Geosciences (GFZ)
etc.
The seismic migration model proposed is still under development. The monitoring results found on the websites of
USGS, were fundamental to the research. Doing the opposite direction to the current research models, using the practice as a means of empirical evidence, along with the media, we forced a deeper inquiry regarding our problem: Is There
An Earthquake Migration Global Pattern?
Acknowledgments
We would like to thank the staff of Quake Red Alert, directly responsible for the elaboration and implementation
of this article. We would also like to thank the teachers
Ana Cecilia Dos Santos and Alexandre J. Schumacher for
their assistance provided. We realize that the non-integration of the seismic observatories databases made this job
more difficult, a situation that can be easily resolved by
adopting a single standard for the measurements, as well
as a unification of the database.
www.quakeredalert.com