Method to Determine Appropriate Source Models of Large Earthquakes Including Tsunami Earthquakes for Tsunami Early Warning in Central America

Abstract

Abstract-Large earthquakes, such as the Mw 7.7 1992 Nicaragua earthquake, have occurred off the Pacific coasts of El Salvador and Nicaragua in Central America and have generated distractive tsunamis along these coasts. It is necessary to determine appropriate fault models before large tsunamis hit the coast. In this study, first, fault parameters were estimated from the W-phase inversion, and then an appropriate fault model was determined from the fault parameters and scaling relationships with a depth dependent rigidity. The method was tested for four large earthquakes, the 1992 Nicaragua tsunami earthquake (Mw7.7), the 2001 El Salvador earthquake (Mw7.7), the 2004 El Astillero earthquake (Mw7.0), and the 2012 El Salvador-Nicaragua earthquake (Mw7.3), which occurred off El Salvador and Nicaragua in Central America. The tsunami numerical simulations were carried out from the determined fault models. We found that the observed tsunami heights, run-up heights, and inundation areas were reasonably well explained by the computed ones. Therefore, our method for tsunami early warning purpose should work to estimate a fault model which reproduces tsunami heights near the coast of El Salvador and Nicaragua due to large earthquakes in the subduction zone.

Performance of uniform and heterogeneous slip distributions for the modeling of the November 2016 off Fukushima earthquake and tsunami, Japan

“…The single-fault model is parameterized by fault length, fault width, fault depth, slip amount, horizontal location, strike, dip, and rake. When the fault length and width are unknown, as is often the case in an immediate analysis soon after an earthquake occurrence, they are determined by a scaling law from the earthquake magnitude (e.g., Tanioka et al 2017). In this study, we used the scaling law proposed by Utsu (2001): where S = LW is the fault area (km 2 ), based on fault length L and fault width W, and M w is the moment magnitude.…”

Determination of Source Models Appropriate for Tsunami Forecasting: Application to Tsunami Earthquakes in Central Sumatra, Indonesia

“…This has been an important issue in Indonesia since the 2010 Mentawai tsunami earthquake. Tanioka et al (2017) recently developed a method combining the W-phase inversion and scaling relationship with a depth-dependent rigidity to estimate an appropriate source model for large earthquakes, including tsunami earthquakes, in Central America.…”

“…The 2010 Mentawai tsunami earthquake that occurred off the west coast of Sumatra had similar characteristics as those of the 1992 Nicaragua tsunami earthquake. In this study, we estimate appropriate rigidities, such as the depth-dependent rigidity used by Tanioka et al (2017), to determine appropriate source models for tsunami height estimations of the 2007 Bengkulu earthquake (M w 8.4) and the 2010 Mentawai tsunami earthquake (M w 7.8). Additionally, we determine the depth-dependent rigidity relation for Central Sumatra in our tsunami height forecasting method.…”

Introduction to “Global Tsunami Science: Past and Future, Volume II”

“…Setiyono et al (2017) develop a new pre-computed inundation forecast system, Near-TIF, and demonstrate its application at Pelabuhan Ratu on the southern coast of Java, Indonesia. In order to obtain accurate information of the earthquake source for warning purposes, Tanioka et al (2017) first perform a W-phase inversion using seismological data and obtain other parameters important for tsunami generation using scaling relationships and depth-dependent rigidity evident in subduction zones. The authors demonstrate this method as part of a conceptual tsunami early warning for Central America.…”