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Geometrical properties of seismicity in California

Ross, Zachary E. and Ben-Zion, Yehuda and Zaliapin, Ilya (2022) Geometrical properties of seismicity in California. Geophysical Journal International, 231 (1). pp. 493-504. ISSN 0956-540X. doi:10.1093/gji/ggac189.

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The spatial geometry of seismicity encodes information about loading and failure processes, as well as properties of the underlying fault structure. Traditional approaches to characterizing geometrical attributes of seismicity rely on assumed locations and geometry of fault surfaces, particularly at depth, where resolution is overall quite poor. In this study, we develop an alternative approach to quantifying geometrical properties of seismicity using techniques from anisotropic point process theory. Our approach does not require prior knowledge about the underlying fault properties. We characterize the geometrical attributes of 32 distinct seismicity regions in California and introduce a simple four class classification scheme that covers the range of geometrical properties observed. Most of the regions classified as having localized seismicity are within northern California, while nearly all of the regions classified as having distributed seismicity are within southern California. In addition, we find that roughly 1 out of 4 regions exhibit orthogonal seismicity structures. The results of this study provide a foundation for future analyses of geometrical properties of seismicity and new observables to compare with numerical modelling studies.

Item Type:Article
Related URLs:
URLURL TypeDescription ItemNorthern California Earthquake Data Center ItemSouthern California Earthquake Data Center
Ross, Zachary E.0000-0002-6343-8400
Ben-Zion, Yehuda0000-0002-9602-2014
Zaliapin, Ilya0000-0001-6257-0517
Additional Information:© The Author(s) 2022. Published by Oxford University Press on behalf of The Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model ( Revision received: 08 October 2021. Received: 08 May 2022. Accepted: 17 May 2022. Published: 19 May 2022. Corrected and typeset: 04 July 2022. The study was funded by the National Science Foundation (Grants EAR-2122168, EAR-2122191 and EAR-2034167) and the Southern California Earthquake Center (based on NSF Cooperative Agreement EAR-1600087 and USGS Cooperative Agreement G17 AC00047). The paper benefitted from useful comments by two anonymous referees and Editor Eiichi Fukuyama. DATA AVAILABILITY. The analysed seismic catalogues are publicly available from the Northern California Earthquake Data Center ( and Southern California Earthquake Data Center (
Group:Seismological Laboratory
Funding AgencyGrant Number
Southern California Earthquake Center (SCEC)UNSPECIFIED
USGSG17 AC00047
Subject Keywords:Spatial analysis, Seismicity and tectonics, Statistical seismology, Crustal structure
Issue or Number:1
Record Number:CaltechAUTHORS:20220804-250023000
Persistent URL:
Official Citation:Zachary E Ross, Yehuda Ben-Zion, Ilya Zaliapin, Geometrical properties of seismicity in California, Geophysical Journal International, Volume 231, Issue 1, October 2022, Pages 493–504,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:116122
Deposited By: George Porter
Deposited On:09 Aug 2022 23:04
Last Modified:09 Aug 2022 23:04

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