Título del libro: Extreme Events: Observations, Modeling, And Economics
Título del capítulo: Extreme Magnitude Earthquakes and their Direct Economic Impacts: A Hybrid Approach
MARIO HUMBERTO CHAVEZ GONZALEZ;
Autores externos:
Idioma:
Año de publicación:
2016
Palabras clave:
LARGE SUBDUCTION EARTHQUAKES; 8 COLIMA-JALISCO; 9 OCTOBER; TOHOKU EARTHQUAKE; TELESEISMIC BODY; FREQUENCY; MEXICO; ZONE; PROPAGATION; RUPTURE
Resumen:
The occurrences of extreme magnitude earthquakes (EME), such as the 11 March 2011 Mw 9 Tohoku, Japan, the 9 May 2008 Mw 7.9 Wenchuan, China, and the 19 September 1985 Mw 8.01 Michoacan, Mexico, which led to a large number of casualties and huge economic losses, have shown that the seismic hazard and risk estimations in these seismotectonic regions were grossly underestimated. Hence, a hybrid approach, which uses both observations and modeling of the earthquake phenomena and its effects on the built environment, is proposed to estimate the probabilities of exceedances of intensities (PEI) of an EME and of their direct economic consequences (PEDEC) due to the damages of spatially distributed infrastructure within the site. The PEIs are obtained by using a modeling procedure, which combines long-period 3D finite difference and high-frequency simulations, to generate samples of 3D synthetic seismograms at a site associated with a given EME scenario. The stochastic and fractal character of the seismic source of the EME are included in the modeling. A machine learning procedure is applied to obtain small-scale spatial distribution of ground intensities at the site due to the EME. The PEDECs are computed by combining cadastral, direct economic costs, and seismic vulnerability functions of the infrastructure of interest, and the spatial distribution of intensities of the EME scenario. Marginals' probability density functions and Copula models are applied to obtain independent and joint probability distributions of the PEI and PEDEC, from which their associated return period () probabilities can be derived for decision-making purposes. The uncertainties (and future updates) of the information required to estimate the PEI and PEDEC can be cascaded throughout the end-to-end computation of the hybrid approach. As recent studies suggest that most of the circum-Pacific subduction zones (which includes the Mexican subduction region) can generate EMEs with Mw >= 8.5, two examples of the application of the proposed hybrid approach to obtain preliminary estimates of PEIs, PEDECs, and probable maximum losses (PMLs) of the direct costs of the damage to one-to three-floor dwelling constructions in Mexico City and Guadalajara due to the potential occurrence of extreme Mw 8.5 subduction magnitude with epicenters in the Mexican Pacific Ocean Coast are presented. The importance of estimating the PEI and PEDEC using bounded (truncated) marginal probability distributions, and considering their stochastic dependence is highlighted. The preliminary PMLs for the extreme Mw 8.5 magnitude scenarios varies from 0.7 to 18 billion USD for Mexico City, and from 37 to 61 billion USD for Guadalajara. The convenience of implementing mitigation policies, such as increasing the seismic strength of the existing (or planned) infrastructure, in combination with taxes and insurance incentives to increase risk mitigation ex-ante event investments are also analyzed. If ex-ante mitigation retrofitting actions are taken to reduce the vulnerabilities of the one- to three-floor dwelling constructions of Mexico City and Guadalajara, similar to 52,000 and similar to 250,000 dwellings could be saved by investing similar to 0.8 and similar to 6 billion USD, versus potential PMLs (due to the extreme Mw 8.5 magnitude scenarios) of similar to 7 and similar to 22 billion USD, respectively.
Entidades citadas de la UNAM:
ISBN:
9781119157045
Editorial:
BLACKWELL SCIENCE PUBL
Tipo de producto:
Article
