89 Advancing Earthquake Geology and Surficial Deformation from Geologic Provinces to Political Entities through Multidisciplinary High-Resolution Data

Understanding earthquakes and surface deformation requires integrating geologic, geophysical, and remote sensing data. This session welcomes research using diverse methods—paleoseismology, LiDAR, structure-from-motion photogrammetry, geochronology, and analog modeling to refine fault behavior, rupture dynamics, segmentation, and recurrence from various tectonic settings.

Monday, 20 October 2025
8:00 AM - 12:00 PM
HBGCC, 217D

Assessing Segment Boundary Controls on Earthquake Rupture in the Eastern Precordillera, Argentina: New Paleoseismic Evidence from the Marquesado Fault

Paper number: 89-3
Program: Technical Sessions
Time: 8:40 AM – 8:55 AM

Authors

  • Shreya Arora Presenting Author
    Bates College, Department of Earth and Climate Sciences, Lewiston, ME
  • Drew Cochran
    Bates College, Lewiston, Maine
  • Yann Klinger
    Institute de Physique du Globe de Paris, IPGP, Paris
  • Gustavo Ortiz
    Departamento de Geofísica y Astronomía, Universidad Nacional de San Juan, San Juan
  • Jeremy Rimando
    Canadian Nuclear Safety Commission, Ottawa
  • Nathan Brown
    University of Texas at Arlington, Arlington, TX
  • Melina Villalobos
    Departamento de Geología, Universidad Nacional de San Juan, San Juan
  • Raul Gomez
    Departamento de Geología, Universidad Nacional de San Juan, San Juan

Abstract

Why do some earthquakes repeatedly rupture discrete fault segments, while others rupture entire faults? Answering this remains fundamental to improving seismic hazard analysis and, in turn, to hazard preparedness and mitigation efforts. Over the past two decades, several mechanisms for rupture termination and propagation have been proposed, including variation in geometric, structural, and geologic characteristics of faults (Aki, 1979; King and Nabelek, 1985). In this study, we investigated the Eastern Precordillera (EPC) of the Andes Mountains in Argentina, which is classified into three segments: Villicum, Las Tapias, and Zonda–Pedernal (Siame et al., 2002) to determine whether the historical surface ruptures associated with major earthquakes crossed the segment boundaries, or whether rupture propagation was arrested by structural asperities, indicating an asperity-controlled behavior. In this study, we focused on three major faults within the Eastern Precordillera (EPC): the La Laja Fault within the Villicum segment, the Marquesado Fault in the Las Tapias segment, and the La Rinconada Fault within the Zonda–Pedernal segment. Each of these faults has at least one existing paleoseismic record that provides insights into past surface-rupturing earthquakes. However, a gap in data remained along a NNE-SSW-striking Marquesado Fault. To address this, we conducted a new paleoseismic investigation at this site to complement and integrate with the preexisting dataset to evaluate the extent of past surface ruptures in relation to fault geometry and structural segmentation. We have compiled the earthquake timing of nine earthquakes. Preliminary results suggest that, of the nine identified events, only one earthquake appears to have ruptured across an ~18 km-long segment gap, including a ~4 km stepover and notable lithologic variation evidence consistent with a multi-segment rupture event.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412113

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