Active Crustal Deformation in the Trans‐Mexican Volcanic Belt as Evidenced by Historical Earthquakes During the Last 450 Years

Abstract

AbstractThe Trans‐Mexican Volcanic Belt (TMVB) is oblique to the subduction zone. Background seismicity is very low. Nevertheless, two large instrumental earthquakes were recorded: the 1912 Acambay (Mw 6.9) and the 1920 Jalapa (Mw 6.4) earthquakes. Macroseismic data were systematically searched for crustal earthquakes on the TMVB contained in historical accounts. The macroseismic reports were inverted for the best fitting magnitude and epicenter. The western end of the TMVB shows the highest level of seismic activity. An earthquake is reported in 1568 (Mw 7.2 ± 0.2) and a second large event took place in 1875 (Mw 7.0 ± 0.2). Two other earthquakes are reported in the western TMVB in 1611 and 1749 (Mw 6.4). The 1858 earthquake (Mw 7.6 ± 0.3), in the central TMVB occurred on faults located to the west of the 1912 Acambay event. The eastern TMVB is less active. An earthquake in 1575 (Mw 5.7) occurred east of the city of Puebla. The 1887 (Mw 6.2 ± 0.2) and the 1920 Jalapa earthquakes are the larger events in this region. The seismicity observed from the instrumental and historical seismicity catalogs show that active tectonic deformation occurs throughout the TMVB and that it is not confined to specific regions where instrumental earthquakes have been located and active faults mapped. The number of large earthquakes in the TMVB, suggest unique large‐scale deformation of this complex volcanic belt. The presence of large earthquakes in this tectonic province, where 40% of the population of Mexico live, underlines the importance of reevaluating hazard in this densely populated region.