Abstract

MARTINEZ-LOPEZ, M. Rosario  and  MENDOZA, Carlos. Sismogenic coupling in theB Michoacán-Colima-Jalisco subduction zone, Mexico. Bol. Soc. Geol. Mex [online]. 2016, vol.68, n.2, pp.199-214. ISSN 1405-3322.

Hypocenters and focal mechanisms of earthquakes in southwestern Mexico between 1964 and 2008 were analyzed to examine the seismogenic width of the Michoacan-Colima-Jalisco subduction zone. This subduction zone includes the Michoacan segment in the northwest portion of the Cocos plate and the Jalisco segment, which corresponds to the Rivera plate. In the Michoacan segment, the maximum depth of seismogenic coupling is approximately 40 km. This depth is greater than the value of 25 km previously proposed for the entire Cocos plate. For the Rivera plate, the maximum seismogenic depth is also 40 km, consistent with the previously proposed value. This value suggests a different seismogenic width for each segment due to the difference in dip between the Cocos and Rivera plates. The dimensions of the seismogenic contact estimated for the Michoacan segment (300 km x 95 km) and for the Jalisco segment (420 km x 75 km) indicate a similar maximum magnitude of Mw 8.3 with an expected average slip of 2 m. These results have important implications for the estimation of the seismic potential in the Michoacan-Colima-Jalisco subduction zone.

Keywords : Seismicity; focal mechanisms; subduction in Mexico; seismogenic zone.