Advances in Geosciences
www.adv-geosci.net
1680-7340
1680-7359
22
4th EGU Alexander von Humboldt Conference "The Andes: Challenge for Geosciences"
2009
10.5194/adgeo-22-139-2009
http://www.adv-geosci.net/22/139/2009/
http://www.adv-geosci.net/22/139/2009/adgeo-22-139-2009.html
http://www.adv-geosci.net/22/139/2009/adgeo-22-139-2009.pdf
139
145
2009-12-14
Latitudinal distribution of earthquakes in the Andes and its peculiarity
B. W. Levin
E. V. Sasorova
Institute of Marine Geology and Geophysics, Far East Branch of Russian Academy of Sciences, Yuzhno-Sakhalinsk, Russia
Shirshov Institute of Oceanology of Russian Academy of Sciences, Moscow, Russia
In the last decade, there has been growing interest in problems related to
searching global spatiotemporal regularities in the distribution of seismic
events on the Earth. The worldwide catalogs ISC were used for search of
spatial and temporal distribution of earthquakes (EQ) in the Pacific part of
South America. We extracted all EQ from 1964 to 2004 with Mb>=4.0. The
total number of events under study is near 30 000. The entire set of events
was divided into six magnitude ranges (MR): 4.0<=Mb<4.5;
4.5<=Mb<5.0; 5.0<=Mb<5.5; 5.5<=Mb<6.0;
6.0<=Mb<6.5; and 6.5<=Mb. Further analysis was performed
separately for each MR. The latitude distributions of the EQ number for all
MR were studied. The whole region was divided in several latitudinal
intervals (size of each interval was either 5° or 10°). The
number of events in each latitudinal interval was normalized two times. After
normalization we obtained the relative seismic event number generated per one
kilometer of plate boundary. The maximum of seismic activity in the Pacific
part of the South America is situated in latitude interval 20°–30° S.
The comparative analysis was executed for the latitude distributions of the
EQ number and the EQ energy released. Then the distributions of EQ hypocenter
location in latitude and in depth were studied. The EQ sources for the high
latitudes (up to 35° S) are located on the depth (H) between 20–80 km.
It was shown, that full interval of depth in each latitudinal belt generally
divides into three parts (clusters) with close-cut separation boundaries
(<i>K</i>1 – with 0<H<=80 km, <i>K</i>2 – with 120<H<=240 km
and
<i>K</i>3 – with H>=500 km).
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