title: Potential for a large earthquake near Los Angeles inferred from the 2014 La Habra earthquake.
abstract: 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 1933M6.4 Long Beach and 1994M6.7 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 2014M5.1 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 futureM6.1-6.3 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.
authors.affiliation: Jet Propulsion Laboratory California Institute of Technology Pasadena California USA; Department of Earth Sciences University of Southern California Loa Angeles California USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Donnellan
authors.affiliation: Program in Public Health University of California Irvine California USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Grant Ludwig
authors.affiliation: Jet Propulsion Laboratory California Institute of Technology Pasadena California USA.
authors.forename: Jay W
authors.initials: JW
authors.lastname: Parker
authors.affiliation: Departments of Physics and Geology University of California Davis California USA.
authors.forename: John B
authors.initials: JB
authors.lastname: Rundle
authors.affiliation: University Information Technology Services Indiana University Bloomington Indiana USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: University Information Technology Services Indiana University Bloomington Indiana USA.
authors.forename: Marlon
authors.initials: M
authors.lastname: Pierce
authors.affiliation: Nevada Geodetic Laboratory Nevada Bureau of Mines and Geology, University of Nevada Reno Nevada.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Blewitt
authors.affiliation: Jet Propulsion Laboratory California Institute of Technology Pasadena California USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Hensley
keywords: GPS; La Habra; UAVSAR; earthquake; geodesy; modeling