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Estimated casualties in a possible great earthquake along the Pacific Coast of Mexico

Max Wyss and F. Ramon Zuniga
Estimated casualties in a possible great earthquake along the Pacific Coast of Mexico
Bulletin of the Seismological Society of America (August 2016) 106 (4): 1867-1874

Abstract

Faults may rupture across several segments of plate boundaries, generating earthquakes of M 9 class. Along the Pacific coast of Mexico, a rupture of 450 km on 28 March 1787 generated an M (sub w) 8.6 earthquake. Intensity values (I) of VII were reported at the Atlantic coast, and the maximum was XI in Oaxaca. Here, we estimate the number of casualties if an M 9 rupture were to occur at present. We verified that our software tool, QLARM, with its database, estimates intensities and fatalities approximately correctly for historic earthquakes along the Pacific coast. Our test set consists of 10 earthquakes (M (sub w) 7.3-8.6) that caused between 0 and approximately 10,000 fatalities between 1787 and 2003. Requirements for a satisfactory match are that the maximum I agrees within 0.5 units, the extent of the I=VII area agrees approximately, and the fatality count differs by not more than a factor of 2 or by 200 fatalities, whichever is larger. Results for Mexico, without the special case of Mexico City, suggest that an M 9 earthquake would cause approximately 27,000 fatalities and 120,000 injuries. Applying amplification factors to the ground motion in 11 of 15 districts, we estimate that, in an M 9 along the Pacific coast, 100,000 people may perish and 480,000 may be injured in Mexico City. The number of people in settlements with fewer than 20,000 inhabitants exposed to large I exceed the exposed population in larger cities by factors of 3-10. The estimated mortality rate in rural areas is several times higher than in major population centers.


ISSN: 0037-1106
EISSN: 1943-3573
Coden: BSSAAP
Serial Title: Bulletin of the Seismological Society of America
Serial Volume: 106
Serial Issue: 4
Title: Estimated casualties in a possible great earthquake along the Pacific Coast of Mexico
Affiliation: International Center for Earth Simulation Foundation, Geneva, Switzerland
Pages: 1867-1874
Published: 201608
Text Language: English
Publisher: Seismological Society of America, Berkeley, CA, United States
References: 22
Accession Number: 2016-085247
Categories: Seismology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 8 tables, sketch map
N14°30'00" - N32°43'00", W117°00'00" - W86°45'00"
Secondary Affiliation: Universidad Nacional Autonoma de Mexico, MEX, Mexico
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Seismological Society of America. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201641
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