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Abstract:
Central America is a seismically active region where six tectonic plates (North America,
Caribbean, Cocos, Nazca, Panama, and South America) interact in a subduction zone with
transform faults and two triple points. This complex tectonic setting makes the maximum
magnitude—Mmax—estimation a challenging task, with the crustal fault earthquakes being
the most damaging in the seismic history of Central America. The empirical source scaling
relations (ESSR) allow the Mmax of faults to be determined from rupture parameters. In this
study, we use a dataset of well-characterized earthquakes in the region, comprising 64
events from 1972 to 2021 with magnitudes between Mw 4.1 and 7.7. The dataset incorporates
records of rupture parameters (length, width, area, slip, and magnitude) and information
on the faults and aftershocks associated. This database is an important product in itself,
and through its use we determine which global relations fit best to our data via a residual
analysis. Moreover, based on the best-quality records, we develop scaling relations for
Central America (CA-ESSR) for rupture length, width, and area. These new relations were
tested and compared with recent earthquakes, and logic trees are proposed to combine
the CA-ESSR and the best-fit global relations. Therefore, we estimate the Mmax for 30 faults
using the logic tree for rupture length, considering a total rupture of the fault andmultifault
scenarios. Our results suggest that in CentralAmerica rupture areas larger than other regions
are required to generate the samemagnitudes.We associate this with the shear modulus (μ),
which seems to be lower (∼ 30% less) than the global mean values for crustal rocks.
Furthermore, considering multifault ruptures, we found several fault systems with potential
Mmax ≥Mw 7.0. These findings contribute to a better understanding of regional seismotectonics
and to the efficient characterization of fault rupture models for seismic hazards.
