High-resolution 3D Seismic Imaging and Aftershock Catalog for the 2021 Mw 7.2, Nippes, Haiti Earthquake
Description:
Less than twelve years after the devastating 2010 Mw 7.0 earthquake, on August 14, 2021, a Mw 7.2 earthquake struck the southern peninsula of Haiti. Following this event, 12 temporary broadband stations were deployed near the rupture area to complement the Raspberry Shake stations that were already installed in the framework of a citizen seismology initiative. Geodetic analysis from previous studies showed that the rupture mechanisms is composed of a combination of thrust motion on the eastern part of the rupture and left-lateral strike-slip motion on the western region. Furthermore, several secondary fault structures were revealed by InSAR phase gradient techniques. Aftershock location from August to December 2021 outlined the main rupture as three north-dipping structures with slightly different strike and dip in the north of the Enriquillo-Plaintain Garden fault (EPGF) and two small clusters on the EPGF near the hypocenter area. However, the secondary fault features were not visible in this initial catalog. Therefore, it is imperative to enhance the aftershock catalog to properly delineate all the active structures that have participated in this event. In this study, we first use a STA/LTA and a Kurtosis algorithm to detect and pick all the arrivals for all the aftershocks that have occurred between the period of August 2021 to January 2023. We then use those detected events as template waveforms and apply a matched filtering analysis that cross-correlate those templates with the continuous data to increase the number of aftershock detection. Furthermore, we then selected 9740 of the well detected events to invert for a 3D Vp and Vs velocity structures which we then use to relocate the entire catalog. Preliminary results show that we are able to significantly increase the number of aftershock detection and better delineate the active structures. Additionally, our 3D velocity model reveals a clear horizontal polarity velocity contrast or bimaterial interface across EPGF fault near the hypocenter area which could have affected the rupture propagation.
Session: Earth’s Structure from the Crust to the Core [Poster]
Type: Poster
Date: 4/16/2025
Presentation Time: 08:00 AM (local time)
Presenting Author: Groniston
Student Presenter: Yes
Invited Presentation:
Poster Number: 93
Authors
Groniston Doreme Presenting Author Corresponding Author gdore002@ucr.edu University of California, Riverside |
Roby Douilly roby.douilly@ucr.edu University of California, Riverside |
Tony Monfret tony.monfret@geoazur.unice.fr Côte d’Azur University, National Center for Scientific Research, French National Research Institute for Sustainable Development, Côte d'Azur Observatory |
Steeve Symithe symithesteevej@gmail.com State University of Haiti |
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High-resolution 3D Seismic Imaging and Aftershock Catalog for the 2021 Mw 7.2, Nippes, Haiti Earthquake
Category
Earth’s Structure from the Crust to the Core