The 2 October 1847 MI 5.7 Chapala Graben Triggered Earthquake (Trans‐Mexican Volcanic Belt, West‐Central Mexico): Macroseismic Observations and Hazard Implications

Abstract

Research Article| November 01, 2017 The 2 October 1847 MI 5.7 Chapala Graben Triggered Earthquake (Trans‐Mexican Volcanic Belt, West‐Central Mexico): Macroseismic Observations and Hazard Implications Max Suter Max Suter aInstituto de Geología, Universidad Nacional Autónoma de México, Estación Regional del Noroeste, Hermosillo, Sonora, Mexico, sutermax@alumnibasel.ch Search for other works by this author on: GSW Google Scholar Seismological Research Letters (2018) 89 (1): 35–46. https://doi.org/10.1785/0220170101 Article history first online: 01 Nov 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Max Suter; The 2 October 1847 MI 5.7 Chapala Graben Triggered Earthquake (Trans‐Mexican Volcanic Belt, West‐Central Mexico): Macroseismic Observations and Hazard Implications. Seismological Research Letters 2017;; 89 (1): 35–46. doi: https://doi.org/10.1785/0220170101 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search ABSTRACT The Trans‐Mexican volcanic belt is an active continental volcanic arc related to subduction along the Middle America trench and characterized by several major arc‐parallel middle Miocene—Holocene lake basins formed by normal faults and related crustal seismicity. The Chapala graben, the largest of these basins in the western part of the Trans‐Mexican volcanic belt, is 115 km long and up to 30 km wide. Here, I document a 2 October 1847 earthquake with intensity magnitude MI of 5.7±0.4 that was locally devastating on the northern graben shoulder. It razed the villages of Poncitlán and Ocotlán in the state of Jalisco, where at least 58 persons perished. The macroseismic observations for this historical event and the elevated background seismicity indicate that the Chapala graben is active and poses a major ground‐shaking hazard to the nearby metropolitan areas of Ocotlán and Guadalajara. No historical earthquake had been previously documented from the Chapala graben, which was believed to be tectonically inactive. Furthermore, the 2 October 1847 event was not recognized as a crustal earthquake. In earthquake catalogs, the devastation at Ocotlán is aggregated with the damage caused on the same day, only two hours earlier, in the Colima region by a subduction‐zone earthquake that was devastating in Tecomán and Colima and caused minor damage in Mexico City, and which likely triggered dynamically the Chapala graben earthquake. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.