{"title":"The Quaternary Active El Arrayan Fault, Santiago, Chile","authors":"J. Araya, G. Pascale, S. Sepúlveda","doi":"10.5027/ANDGEOV48N3-3256","DOIUrl":null,"url":null,"abstract":"Understanding the location and nature of Quaternary active crustal faults is critical to the reduction of both fault rupture and strong ground motions hazards in the built environment. Recent work along the San Ramon Fault in Santiago, Chile demonstrates that crustal seismic sources are important hazards. We present the results of a second likely Quaternary active fault (the El Arrayan Fault, EAF) that runs through the City of Santiago. The EAF was discovered at an outcrop in El Arrayan (Lo Barnechea) with up to the North reverse motion and sinistral (left-lateral) motion clearly visible and coincident with fault rocks (gouge, cataclasite, and breccia) and higher topography (i.e. uplift) in the hanging wall. The EAF is at least 12 km long, strikes North-Northwest to South-Southeast, and is steeply dipping (mean dip 77º NE). Clear geomorphic expression with sinistral displaced streams (up to ~210 m) suggest that this fault is Quaternary active and an important local source of fault rupture and crustal strong ground motions. Because no fault zone avoidance criteria in Chile, there is need for enhanced fault mapping, legislation, implementation of active fault rupture avoidance areas in Chile to reduce the risk posed by active crustal structures.","PeriodicalId":49108,"journal":{"name":"Andean Geology","volume":"48 1","pages":""},"PeriodicalIF":0.9000,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Andean Geology","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.5027/ANDGEOV48N3-3256","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOLOGY","Score":null,"Total":0}
引用次数: 1
Abstract
Understanding the location and nature of Quaternary active crustal faults is critical to the reduction of both fault rupture and strong ground motions hazards in the built environment. Recent work along the San Ramon Fault in Santiago, Chile demonstrates that crustal seismic sources are important hazards. We present the results of a second likely Quaternary active fault (the El Arrayan Fault, EAF) that runs through the City of Santiago. The EAF was discovered at an outcrop in El Arrayan (Lo Barnechea) with up to the North reverse motion and sinistral (left-lateral) motion clearly visible and coincident with fault rocks (gouge, cataclasite, and breccia) and higher topography (i.e. uplift) in the hanging wall. The EAF is at least 12 km long, strikes North-Northwest to South-Southeast, and is steeply dipping (mean dip 77º NE). Clear geomorphic expression with sinistral displaced streams (up to ~210 m) suggest that this fault is Quaternary active and an important local source of fault rupture and crustal strong ground motions. Because no fault zone avoidance criteria in Chile, there is need for enhanced fault mapping, legislation, implementation of active fault rupture avoidance areas in Chile to reduce the risk posed by active crustal structures.
期刊介绍:
This journal publishes original and review articles on geology and related sciences, in Spanish or English, in three issues a year (January, May and September). Articles or notes on major topics of broad interest in Earth Sciences dealing with the geology of South and Central America and Antarctica, and particularly of the Andes, are welcomed.
The journal is interested in publishing thematic sets of papers and accepts articles dealing with systematic Paleontology only if their main focus is the chronostratigraphical, paleoecological and/or paleogeographical importance of the taxa described therein.