HR: 08:25h
AN: U31B-02    [Abstracts]
TI: Extreme Subduction Earthquake Scenarios and their Economical Consequences for Mexico City and Guadalajara, Jalisco, Mexico
AU: * Chavez, M
EM: marioch48@yahoo.com
AF: Institute of Engineering, UNAM, Apdo. 70-569, Mexico City, 04510, Mexico
AU: * Chavez, M
EM: marioch48@yahoo.com
AF: Lab.Geol. TAO, ENS, 24, Rue Lhomond, Paris, 75231, France
AU: Cabrera, E
EM: eccf@super.unam.mx
AF: DGSCA, Circ. Esc. SN,Cdad. Universitaria, Mexico City, 04510, Mexico
AU: Perea, N
EM: narpere@yahoo.com
AF: Institute of Engineering, UNAM, Apdo. 70-569, Mexico City, 04510, Mexico
AB: The destructive effects of large magnitude, thrust subduction superficial (TSS) earthquakes on Mexico City (MC) and Guadalajara (G) has been shown in the recent centuries. For example, the 7/04/1845 a TSS earthquake with Ms 7+ and epicentral distance of about 250 km from MC occurred on the coast of the state of Guerrero, a Maximum Mercalli Modified Intensity (MMI) of IX-X was reported in MC. Furthermore, the 19/09/1985 a Ms 8.1, Mw 8.01, TSS earthquake with epicentral distance of about 340 km from MC occurred on the coast of the state of Michoacan, a maximum MMI of IX-X was reported in MC. Also, the largest, Ms 8.2, instrumentally observed TSS earthquake in Mexico, occurred in the Colima-Jalisco region the 3/06/1932, with epicentral distance of the order of 200 km from G in northwestern Mexico. The 9/10/1995 another similar event, Ms 7.4, Mw 8, with an epicentral distance of about 240 km from G, occurred in the same region and produced MMI IX in the epicentral zone and MMI up to VI in G. The frequency of occurrence of large TSS earthquakes in Mexico is poorly known, but it might vary from decades to centuries [1]. On the other hand, the first recordings of strong ground motions in MC dates from the early 1960īs and most of them were recorded after the 19/09/1985 earthquake. In G there is only one recording of the later event, and 13 for the one occurred the 9/10/1995 [2]. In order to fulfill the lack of strong ground motions records for large damaging TSS earthquakes, which could have an important economical impact on MC [3] and G, in this work we have modeled broadband synthetics (obtained with a hybrid model that has already been satisfactorily compared with observations of the 9/10/1995 Colima-Jalisco Mw 8 earthquake, [4]) expected in MC and G, associated to extreme magnitude Mw 8.5, TSS scenario earthquakes with epicenters in the so-called Guerrero gap and in the Colima-Jalisco zone, respectively. The proposed scenarios are based on the seismic history and up to date seismotectonic, seismological, geophysical, and geotechnical information for the mentioned subduction zones and for MC and G. The economical impacts of the proposed extreme TSS earthquake scenarios for MC and G are fully discussed. We acknowledge the support of DGSCA, UNAM, for using its supercomputer facilities. ----------------------- [1] Nishenko S.P. and Singh SK, BSSA 77, 6, 1987 [2] Chavez M. and Ramirez R., 12th World Conf. Earthq. Eng., 2000 [3] Cabrera E., Chavez M., Madariaga R., Mai M, Frisenda M., Perea N., AGU, Fall Meeting, 2005 [4] Chavez M., Olsen K.B., Cabrera E., 13th World Conf. Earthq. Eng., 2004
DE: 3300 ATMOSPHERIC PROCESSES
DE: 4400 NONLINEAR GEOPHYSICS (3200, 6944, 7839)
SC: Union [U]
MN: 2007 Joint Assembly