Potential for a large earthquake near Los Angeles inferred from the 2014 La Habra earthquake. Issue 9 (30th September 2015)

• Record Type: Journal Article
• Authors: Donnellan, Andrea; Grant Ludwig, Lisa; Parker, Jay W.; Rundle, John B.; Wang, Jun; Pierce, Marlon; Blewitt, Geoffrey; Hensley, Scott
• Is Part Of: Earth and space science. Volume 2:Issue 9(2015:Sep.)
• Page Start: 378
• Page End: 385
• Publication Date: 2015-09-30
• Subjects: Space sciences -- Periodicals; Geophysics -- Periodicals; 500.5
• DOI: 10.1002/2015EA000113
• Languages: English
• ISSNs: 2333-5084

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>Tectonic motion across the Los Angeles region is distributed across an intricate network of strike‐slip and thrust faults that will be released in destructive earthquakes similar to or larger than the 1933 <italic>M</italic>6.4 Long Beach and 1994 <italic>M</italic>6.7 Northridge events. Here we show that Los Angeles regional thrust, strike‐slip, and oblique faults are connected and move concurrently with measurable surface deformation, even in moderate magnitude earthquakes, as part of a fault system that accommodates north‐south shortening and westerly tectonic escape of northern Los Angeles. The 28 March 2014 <italic>M</italic>5.1 La Habra earthquake occurred on a northeast striking, northwest dipping left‐lateral oblique thrust fault northeast of Los Angeles. We present crustal deformation observation spanning the earthquake showing that concurrent deformation occurred on several structures in the shallow crust. The seismic moment of the earthquake is 82% of the total geodetic moment released. Slip within the unconsolidated upper sedimentary layer may reflect shallow release of accumulated strain on still‐locked deeper structures. A future <italic>M</italic>6.1–6.3 earthquake would account for the accumulated strain. Such an event could occur on any one or several of these faults, which may not have been identified by geologic surface mapping.</p> </abstract>