Probabilistic seismic hazard assessment for Western Mexico
Por:
Sawires, Rashad, Pelaez, Jose A., Santoyo, Miguel A.
Publicada:
1 feb 2023
Resumen:
An updated probabilistic seismic hazard analysis in terms of peak ground
acceleration and spectral acceleration values, for B, B/C, and C NEHRP
site classes, for a 5% and 10% probability of exceedance in 50 years,
has been conducted for Western Mexico. To achieve this assessment, a
unified and updated declustered earthquake catalog (1787-2019), as well
as an updated focal mechanism database (1963-2016), was compiled,
prepared, and processed specifically for this work. Two alternative
source models (area sources and a spatially smoothed seismicity model)
were considered in the assessment, within a logic tree scheme. A
characteristic earthquake model has been also implemented for some of
the defined sources. The designed logic tree has additionally included
other parameters: the possible uncertainty related to the
Gutenberg-Richter b-value way of estimation, the maximum expected
magnitude value, as well as two-alternative GMPEs selected for the
subduction seismic sources. The obtained ground-motion results have been
presented as seismic hazard isoacceleration maps, as well as uniform
hazard spectra and hazard curves for 15 selected cities, for the three
considered site conditions. A comparison between the obtained hazard
values and the current seismic design regulations, as well as previous
studies, has been also performed, and a new design response spectrum has
been proposed. Finally, some regression fitting relationships between
the obtained ground-motion values have been achieved. Concerning the
most significant results, it is worth noting that the southwestern coast
(in the perimeter of the Middle America Trench of the Mexican Subduction
Zone) presents the highest hazard values. For instance, the cities of
Apatzing ` an, Autl ` an, Colima, L ` azaro C ` ardenas, and Manzanillo
exhibit the largest observed PGA values among all the studied cities.
Our approach and results are supported by the fact that the recent
September 19, 2022, Mw 7.6 earthquake has been located in this highest
seismic hazard area.
Filiaciones:
Sawires, Rashad:
Assiut Univ, Fac Sci, Dept Geol, Assiut 71516, Egypt
Pelaez, Jose A.:
Univ Jaen, Dept Phys, Jaen 23071, Spain
Santoyo, Miguel A.:
Natl Autonomous Univ Mexico UNAM, Inst Geophys, Ave Univ, Mexico City 3000, DF, Mexico
|