Large-magnitude Central American earthquakes, 1898-1994

Abstract

S U M M A R YWe have collected and re-examined macroseismic information for large Central American earthquakes since the beginning of the period of instrumental recording about one hundred years ago, and combined this with a reassessment of early instrumental information to produce a catalogue of 51 events that we believe includes all those with magnitudes (Ms) greater than 7.0. We have reassessed surface-wave magnitudes by consulting station bulletins and we have derived a correction that gives an equivalent Ms for events of intermediate depth. We have also developed a regional relationship between Ms and seismic moment, which enables us to estimate the seismic slip rate across the Middle American Trench. Our best estimates give an average slip rate several times smaller than suggested convergence rates, but with the seismic slip in the central segment of the trench almost an order of magnitude smaller than that in the segments on either side. The low seismic slip rate may indicate aseismic crustal deformation

A New Digital Accelerograph Network for El Salvador

“…The subduction of the Cocos plate defines the Middle American Trench, and this thrust interface is a major source of earthquake activity, with steep Benioff-Wadati zones descending to about 300 km. The largest instrumentally recorded earthquakes on this interface have had magnitude of about 8 (Dewey and Suarez, 1991), but the section of the trench off the coast of E1 Salvador has been shown to have a relatively low seismic slip rate and the largest events this century have had magnitudes between 7.1 and 7.3 (Ambraseys and Adams, 1996). Nonetheless, of the 14 earthquakes that have caused destruction in San Salvador since 1700, only five were directly associated with the subduction of the Cocos plate.…”

“…Figure 5 shows examples of accelerograms from a subduction event and from a volcanic chain event. The subduction event occurred on 19 June 1982, about 60 km southwest of San Salvador with a focal depth of 80 km and surface-wave magnitude M, = 7.3 (Ambraseys and Adams, 1996). This earthquake was felt throughout most of E1 Salvador and resulted in 8 deaths and damage to about 1,630 dwellings (Alvarez, 1982).…”

Geomorphic analysis of transient landscapes in the Sierra Madre de Chiapas and Maya Mountains (northern Central America): implications for the North American–Caribbean–Cocos plate boundary

“…These faults are seismically active ( Fig. 3a; White, 1984;Singh et al, 1984;Ambraseys and Adams, 1996;Guzmán-Speziale, 2010) and Quaternary displacements are documented (e.g., Burkart, 1978Burkart, , 1983Authemayou et al, 2012). described a relict middle Miocene planation surface which formed at low elevation and covered most of the Polochic-Motagua sliver (the so-called "Mayan paleosurface").…”

Daños, efectos y amenaza de tsunamis en América Central

“…La tripulación del barco de guerra estadounidense Dixie, sintió severamente el movimiento de las aguas (González, 1910;Camacho & Víquez, 1993;Ambraseys & Adams, 1996).…”