15:30 〜 16:30
[S13-P-08] Rupture process of the Ms 7.4 November 15, 2004 Colombia earthquake
The subduction zone in the northwestern part of the South American plate presents a complex tectonic process due to the interaction between the Nazca, Cocos and Caribbean plates. Analyzing the rupture process in this region is of great importance to understand the occurrence of seismic events in Colombia. We have determined the space-time distribution of the slip on the fault plane for the November 15th, 2004 earthquake, located in the Colombian-Ecuadorian trench in the Colombian Pacific subduction zone. This event is one of the most shallow and significant in recent years because it occurred in the region where the largest earthquakes have been reported such as the 1906 (Mw=8.8), 1942 (7.9), 1958 (Mw=7.8) and the 1979 (Mw=8.2). We applied the inversion method developed by Yagi et al. (2003) using the P waveform modeling at teleseismic distances, which is a numerical method that calculates the slip distribution on the fault plane assuming a seismic source as a sequence of point sources. The slip distribution obtained is the one that best retrieves the observed records in several teleseismic stations. The parameters that best fit to describe the process of rupture of this event were: strike= 177, dip= 79, slip= 85, depth h = 15 km. The rupture process obtained indicates that the rupture propagates towards the surface with a maximum slip of 3.7 m at depth of 15 km. The temporal function for this event shows a complex rupture with two peaks and a total duration of 15 seconds.