Rapid Estimation of Fault Parameters for Tsunami Warning along the Mexican Subduction Zone: A Scenario Earthquake in the Guerrero Seismic Gap

Abstract

Online Material: Color figures; synthetic‐data links. The devastating tsunami produced by the Sumatra–Andaman earthquake ( M w 9.2) of 24 December 2004 heightened the interest of the scientific community in tsunami early warning systems. Global efforts have been successful in achieving a robust ocean basin‐wide tsunami warning in which there is enough time to obtain accurate source parameters, determine the tsunami potential, model the tsunami propagation through the oceans, and update it with real‐time sea‐surface height observations. However, local systems are still not reliable. In such cases, rapid estimation of accurate source parameters that are expeditious in discriminating a tsunamigenic earthquake and its potential tsunami are essential. The 2011 Tohoku–Oki earthquake ( M w 9.0) revealed that tsunami‐warning techniques based on traditional seismic instrumentation could lead to an underestimation of the event magnitude (Ozaki, 2011), which can translate into tragic loss of life and infrastructure (e.g., Cyranosky, 2011). The Pacific coast of Mexico has been struck by at least 26 historic tsunamis originating from local subduction earthquakes (Sanchez and Farreras, 1993; Farreras, 1997). Tide‐gauge recording in Mexico began in 1952. Since then, the maximum height recorded is 3 m for the 1985 Michoacan earthquake ( M w 8.0). However, historic documents suggest that tsunamis as high as 8–11 m may have hit the Mexican Pacific coast during the Guerrero–Oaxaca earthquake of 28 March 1787, M w 8.4–8.6 (Sanchez and Farreras, 1993; Farreras, 1997; Nunez‐Cornu et al. , 2008; Suarez and Albini, 2009) and the Colima–Jalisco earthquake of 22 June 1932, M w 7.0 (Sanchez and Farreras, 1993; Farreras, 1997). An effective tsunami early warning system for the Mexican Pacific coast should be able to emit a reliable alert in less than 10 minutes, given that the peak in the tsunami height may reach the coast about 10–15 minutes after the …