Browsing by Author "Wang, Yuchen"

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    Seismic Source of 1966 Huacho Peru Earthquake (Mw 8.1) from Tsunami Waveform Inversion
    (2023) Jimenez, Cesar; Carbonel, Carlos; Villegas-Lanza, J. C.; Quiroz, Marco; Wang, Yuchen
    In this research we estimated the slip distribution of the 1966 Huacho Peru earthquake, by inverting tsunami waveforms. This event took place offshore the central Peru region and produced severe ground shaking in the cities of Supe and Huacho, with intensities of VIII MM, leading to 100 fatalities. The coseismic seabed deformation produced by the earthquake triggered a regional tsunami that inundated some coastal areas, with major effects in Casma and Tortugas. We used the tsunami waveforms from three tidal stations located in Chimbote, Callao and Marcona, to obtain the parameters of the seismic source through an inversion process, whereby we compared the simulated and observed waveforms using the non-negative least square approach. Our results show a dislocation with a maximum slip of 5.5 m located around the epicentre. This implies that the asperity with maximum energy release was located offshore Barranca city. The seismic moment was calculated as 2.05x10(21) Nm, which is equivalent to a moment magnitude of 8.1 Mw. We suggest that there is a high potential for the generation of a tsunamigenic earthquake in the central region of Peru, despite the occurrence of the 1966 Peruvian earthquake, because this earthquake (together with the 1940, 1974 and 2007 earthquakes) has only released around the 20% of the energy accumulated from the 1746 earthquake (Mw9.0).
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    Tsunami early warning system using offshore tsunameters in Peru
    (2023) Wang, Yuchen; Jiménez, Cesar; Quiroz Valeria, Marco Enrique; Ortega, Erick
    Earthquakes occurring in the Peru-Chile Trench can trigger tsunamis that damage the Peruvian coast. The Directorate of Hydrography and Navigation plans to install three offshore tsunameters in 2023. We propose a tsunami early warning system that uses these tsunameters and targets the Lima Metropolitan Area (LMA), based on the inversion of the initial sea-surface distribution and the superposition of Green's function. Four coastal stations were selected to test the system using historical tsunami events. The forecasts made 15 min after the earthquake had accuracies of 77.0% and 19.4% for the 1966 Huacho and 2001 Camana earthquakes, respectively, whereas the forecasts made 30 min after the earthquake had accuracies of 82.4% and 98.9% for the 1966 and 2001 events, respectively. These results confirmed that the three planned offshore tsunameters will be reliable for making tsunami early warning for the LMA. Moreover, we tested the system using six and ten offshore tsunameters. An increase in the number of offshore tsunameters generally improved the forecast accuracy, but the improvement was not significant. This study is the first to investigate a tsunami early warning algorithm using offshore tsunameters for the Peruvian coast. The results are helpful in mitigating coastal hazards at a reasonable cost.