The 12 May 2008 Mw 7.9 Wenchuan, China, Earthquake: Macroseismic Intensity Assessment Using the EMS-98 and ESI 2007 Scales and Their Correlation with the Geological Structure

Abstract

The Wenchuan earthquake of 12 May 2008 in Sichuan Province, China, can be classified as a large-scale event based on the tectonic structures that triggered the earthquake and the effects caused on the human, structural, and natural environment. This paper presents the geotectonic and seismotectonic regime of the earthquake-affected region on the basis of field data obtained along the seismic fault zone and provides: (1) an estimation of the intensity values according to the EMS-98 and the ESI 2007 scales and the determination of their large-scale geographical distribution along the causative tectonic structure, (2) an interpretation of the intensity distribution according to the seismotectonic, geodynamic, and geotechnical framework, and (3) a comparison between two different intensity scales, the EMS-98 (which is essentially based on the effects on the built environment) and the ESI 2007 (which is based on earthquake environmental effects). The application of both EMS-98 and ESI 2007 and the comparative review and evaluation of the results indicate that the estimated values of the EMS-98 and the ESI 2007 were similar. This suggests that both scales can be useful and reliable tools for seismic hazard estimation.