skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Directivity Modes of Earthquake Populations with Unsupervised Learning

Abstract

We present a novel approach for resolving modes of rupture directivity in large populations of earthquakes. A seismic spectral decomposition technique is used to first produce relative measurements of radiated energy for earthquakes in a spatially compact cluster. The azimuthal distribution of energy for each earthquake is then assumed to result from one of several distinct modes of rupture propagation. Rather than fitting a kinematic rupture model to determine the most likely mode of rupture propagation, we instead treat the modes as latent variables and learn them with a Gaussian mixture model. The mixture model simultaneously determines the number of events that best identify with each mode. The technique is demonstrated on four datasets in California, each with compact clusters of several thousand earthquakes with comparable slip mechanisms. We show that the datasets naturally decompose into distinct rupture propagation modes that correspond to different rupture directions, and the fault plane is unambiguously identified for all cases. We find that these small earthquakes exhibit unilateral ruptures 63–73% of the time on average. Here, the results provide important observational constraints on the physics of earthquakes and faults.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1];  [1]
  1. California Institute of Technology (CalTech), Pasadena, CA (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program; National Science Foundation (NSF)
OSTI Identifier:
1604037
Report Number(s):
LA-UR-19-26206
Journal ID: ISSN 2169-9313
Grant/Contract Number:  
89233218CNA000001; CCF‐1254106; AFOSR YIPFA9550‐15‐1‐0221
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Solid Earth
Additional Journal Information:
Journal Volume: 125; Journal Issue: 2; Journal ID: ISSN 2169-9313
Publisher:
American Geophysical Union
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; Earth Sciences

Citation Formats

Ross, Zachary E., Trugman, Daniel Taylor, Azizzadenesheli, Kamyar, and Anandkumar, Anima. Directivity Modes of Earthquake Populations with Unsupervised Learning. United States: N. p., 2020. Web. doi:10.1029/2019JB018299.
Ross, Zachary E., Trugman, Daniel Taylor, Azizzadenesheli, Kamyar, & Anandkumar, Anima. Directivity Modes of Earthquake Populations with Unsupervised Learning. United States. doi:https://doi.org/10.1029/2019JB018299
Ross, Zachary E., Trugman, Daniel Taylor, Azizzadenesheli, Kamyar, and Anandkumar, Anima. Wed . "Directivity Modes of Earthquake Populations with Unsupervised Learning". United States. doi:https://doi.org/10.1029/2019JB018299. https://www.osti.gov/servlets/purl/1604037.
@article{osti_1604037,
title = {Directivity Modes of Earthquake Populations with Unsupervised Learning},
author = {Ross, Zachary E. and Trugman, Daniel Taylor and Azizzadenesheli, Kamyar and Anandkumar, Anima},
abstractNote = {We present a novel approach for resolving modes of rupture directivity in large populations of earthquakes. A seismic spectral decomposition technique is used to first produce relative measurements of radiated energy for earthquakes in a spatially compact cluster. The azimuthal distribution of energy for each earthquake is then assumed to result from one of several distinct modes of rupture propagation. Rather than fitting a kinematic rupture model to determine the most likely mode of rupture propagation, we instead treat the modes as latent variables and learn them with a Gaussian mixture model. The mixture model simultaneously determines the number of events that best identify with each mode. The technique is demonstrated on four datasets in California, each with compact clusters of several thousand earthquakes with comparable slip mechanisms. We show that the datasets naturally decompose into distinct rupture propagation modes that correspond to different rupture directions, and the fault plane is unambiguously identified for all cases. We find that these small earthquakes exhibit unilateral ruptures 63–73% of the time on average. Here, the results provide important observational constraints on the physics of earthquakes and faults.},
doi = {10.1029/2019JB018299},
journal = {Journal of Geophysical Research. Solid Earth},
number = 2,
volume = 125,
place = {United States},
year = {2020},
month = {2}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share:

Works referenced in this record:

The wrinkle-like slip pulse is not important in earthquake dynamics
journal, January 2005

  • Andrews, D. J.; Harris, Ruth A.
  • Geophysical Research Letters, Vol. 32, Issue 23
  • DOI: 10.1029/2005GL023996

Rupture characteristics of major and great ( M w   ≥ 7.0) megathrust earthquakes from 1990 to 2015: 1. Source parameter scaling relationships
journal, February 2016

  • Ye, Lingling; Lay, Thorne; Kanamori, Hiroo
  • Journal of Geophysical Research: Solid Earth, Vol. 121, Issue 2
  • DOI: 10.1002/2015JB012426

Diminishing high‐frequency directivity due to a source effect: Empirical evidence from small earthquakes in the Abruzzo region, Italy
journal, May 2016

  • Pacor, F.; Gallovič, F.; Puglia, R.
  • Geophysical Research Letters, Vol. 43, Issue 10
  • DOI: 10.1002/2016GL068546

Pulse-like partial ruptures and high-frequency radiation at creeping-locked transition during megathrust earthquakes: Partial Ruptures on Megathrusts
journal, August 2017

  • Michel, Sylvain; Avouac, Jean-Philippe; Lapusta, Nadia
  • Geophysical Research Letters, Vol. 44, Issue 16
  • DOI: 10.1002/2017GL074725

Rupture Directivity Characteristics of the 2003 Big Bear Sequence
journal, May 2010

  • Tan, Y.; Helmberger, D.
  • Bulletin of the Seismological Society of America, Vol. 100, Issue 3
  • DOI: 10.1785/0120090074

Unstable slippage across a fault that separates elastic media of different elastic constants
journal, March 1980


Importance of bimaterial interfaces for earthquake dynamics and strong ground motion
journal, August 2009


Slow‐Growing and Extended‐Duration Seismicity Swarms: Reactivating Joints or Foliations in the Cahuilla Valley Pluton, Central Peninsular Ranges, Southern California
journal, April 2019

  • Hauksson, Egill; Ross, Zachary E.; Cochran, Elizabeth
  • Journal of Geophysical Research: Solid Earth, Vol. 124, Issue 4
  • DOI: 10.1029/2019JB017494

Comment on “The wrinkle-like slip pulse is not important in earthquake dynamics” by D. J. Andrews and R. A. Harris
journal, January 2006


Comment on “Material contrast does not predict earthquake rupture propagation direction” by R. A. Harris and S. M. Day
journal, January 2006


Ground Motion Prediction Equations in the San Jacinto Fault Zone: Significant Effects of Rupture Directivity and Fault Zone Amplification
journal, May 2014


Improved Model Fitting for the Empirical Green's Function Approach Using Hierarchical Models
journal, April 2018

  • Van Houtte, Chris; Denolle, Marine
  • Journal of Geophysical Research: Solid Earth, Vol. 123, Issue 4
  • DOI: 10.1002/2017JB014943

Wrinkle-like slip pulse on a fault between different materials
journal, January 1997

  • Andrews, D. J.; Ben-Zion, Y.
  • Journal of Geophysical Research: Solid Earth, Vol. 102, Issue B1
  • DOI: 10.1029/96JB02856

NGA-West2 Research Project
journal, August 2014

  • Bozorgnia, Yousef; Abrahamson, Norman A.; Atik, Linda Al
  • Earthquake Spectra, Vol. 30, Issue 3
  • DOI: 10.1193/072113EQS209M

On the relation of earthquake stress drop and ground motion variability: Stress Drop and Ground Motion Variability
journal, July 2017

  • Oth, Adrien; Miyake, Hiroe; Bindi, Dino
  • Journal of Geophysical Research: Solid Earth, Vol. 122, Issue 7
  • DOI: 10.1002/2017JB014026

Application of an improved spectral decomposition method to examine earthquake source scaling in Southern California: EARTHQUAKE SOURCE SCALING IN SOUTHERN CALIFORNIA
journal, April 2017

  • Trugman, Daniel T.; Shearer, Peter M.
  • Journal of Geophysical Research: Solid Earth, Vol. 122, Issue 4
  • DOI: 10.1002/2017JB013971

Comprehensive analysis of earthquake source spectra in southern California: SOUTHERN CALIFORNIA SOURCE SPECTRA
journal, June 2006

  • Shearer, Peter M.; Prieto, Germán A.; Hauksson, Egill
  • Journal of Geophysical Research: Solid Earth, Vol. 111, Issue B6
  • DOI: 10.1029/2005JB003979

Asymmetric distribution of aftershocks on large faults in California: Asymmetric aftershocks on bimaterial faults
journal, March 2011


Seismic Imaging of a Bimaterial Interface Along the Hayward Fault, CA, with Fault Zone Head Waves and Direct P Arrivals
journal, February 2014


Cracks, pulses and macroscopic asymmetry of dynamic rupture on a bimaterial interface with velocity-weakening friction
journal, May 2008


Source pulse enhancement by deconvolution of an empirical Green's function
journal, January 1985


Rupture directivity of small earthquakes at Parkfield: PARKFIELD RUPTURE DIRECTIVITY
journal, January 2013

  • Kane, Deborah L.; Shearer, Peter M.; Goertz-Allmann, Bettina P.
  • Journal of Geophysical Research: Solid Earth, Vol. 118, Issue 1
  • DOI: 10.1029/2012JB009675

Teleseismic inversion for the second-degree moments of earthquake space-time distributions
journal, June 2001


Material contrast does not predict earthquake rupture propagation direction
journal, January 2005

  • Harris, Ruth A.; Day, Steven M.
  • Geophysical Research Letters, Vol. 32, Issue 23
  • DOI: 10.1029/2005GL023941

Maximum Likelihood from Incomplete Data Via the EM Algorithm
journal, September 1977

  • Dempster, A. P.; Laird, N. M.; Rubin, D. B.
  • Journal of the Royal Statistical Society: Series B (Methodological), Vol. 39, Issue 1
  • DOI: 10.1111/j.2517-6161.1977.tb01600.x

Investigating uncertainties in empirical Green's function analysis of earthquake source parameters: UNCERTAINTIES IN EGF ANALYSIS
journal, June 2015

  • Abercrombie, Rachel E.
  • Journal of Geophysical Research: Solid Earth, Vol. 120, Issue 6
  • DOI: 10.1002/2015JB011984

Stress drop and source scaling of the 2009 April L’Aquila earthquakes
journal, November 2012

  • Calderoni, Giovanna; Rovelli, Antonio; Singh, Shri Krishna
  • Geophysical Journal International, Vol. 192, Issue 1
  • DOI: 10.1093/gji/ggs011

Rupture directivity of microearthquake sequences near Parkfield, California: MICROEARTHQUAKE DIRECTIVITY AT PARKFIELD
journal, April 2011

  • Lengliné, O.; Got, J. -L.
  • Geophysical Research Letters, Vol. 38, Issue 8
  • DOI: 10.1029/2011GL047303

Three-Dimensional Compressional Wavespeed Model, Earthquake Relocations, and Focal Mechanisms for the Parkfield, California, Region
journal, September 2006

  • Thurber, C.
  • Bulletin of the Seismological Society of America, Vol. 96, Issue 4B
  • DOI: 10.1785/0120050825

The Persistence of Directivity in Small Earthquakes
journal, December 2007

  • Boatwright, J.
  • Bulletin of the Seismological Society of America, Vol. 97, Issue 6
  • DOI: 10.1785/0120050228

Earthquake Directivity, Orientation, and Stress Drop Within the Subducting Plate at the Hikurangi Margin, New Zealand: Directivity of New Zealand Earthquakes
journal, December 2017

  • Abercrombie, Rachel E.; Poli, Piero; Bannister, Stephen
  • Journal of Geophysical Research: Solid Earth, Vol. 122, Issue 12
  • DOI: 10.1002/2017JB014935

Rupture Directivity of the Strongest 2016-2017 Central Italy Earthquakes: Directivity of central Italy earthquakes
journal, November 2017

  • Calderoni, Giovanna; Rovelli, Antonio; Di Giovambattista, Rita
  • Journal of Geophysical Research: Solid Earth, Vol. 122, Issue 11
  • DOI: 10.1002/2017JB014118

Predominance of Unilateral Rupture for a Global Catalog of Large Earthquakes
journal, December 2002

  • McGuire, J. J.
  • Bulletin of the Seismological Society of America, Vol. 92, Issue 8
  • DOI: 10.1785/0120010293

Rupture directivity of microearthquakes on the San Andreas Fault from spectral ratio inversion: Bimaterial microearthquake directivity
journal, June 2011


Estimating Finite Source Properties of Small Earthquake Ruptures
journal, April 2004

  • McGuire, J. J.
  • Bulletin of the Seismological Society of America, Vol. 94, Issue 2
  • DOI: 10.1785/0120030091

Strong Correlation between Stress Drop and Peak Ground Acceleration for Recent M 1–4 Earthquakes in the San Francisco Bay Area
journal, March 2018

  • Trugman, Daniel T.; Shearer, Peter M.
  • Bulletin of the Seismological Society of America, Vol. 108, Issue 2
  • DOI: 10.1785/0120170245

Observational constraints on the fracture energy of subduction zone earthquakes: FRACTURE ENERGY OF EARTHQUAKES
journal, May 2004

  • Venkataraman, Anupama; Kanamori, Hiroo
  • Journal of Geophysical Research: Solid Earth, Vol. 109, Issue B5
  • DOI: 10.1029/2003JB002549

Recent and future developments in earthquake ground motion estimation
journal, September 2016


Toward reliable automated estimates of earthquake source properties from body wave spectra: AUTOMATED ESTIMATES OF SOURCE PROPERTIES
journal, June 2016

  • Ross, Zachary E.; Ben-Zion, Yehuda
  • Journal of Geophysical Research: Solid Earth, Vol. 121, Issue 6
  • DOI: 10.1002/2016JB013003

Effect of directivity on estimates of radiated seismic energy: DIRECTIVITY AND RADIATED SEISMIC ENERGY
journal, April 2004

  • Venkataraman, Anupama; Kanamori, Hiroo
  • Journal of Geophysical Research: Solid Earth, Vol. 109, Issue B4
  • DOI: 10.1029/2003JB002548

Comparing EGF Methods for Estimating Corner Frequency and Stress Drop From P Wave Spectra
journal, April 2019

  • Shearer, Peter M.; Abercrombie, Rachel E.; Trugman, Daniel T.
  • Journal of Geophysical Research: Solid Earth, Vol. 124, Issue 4
  • DOI: 10.1029/2018JB016957

Inverting geodetic time series with a principal component analysis-based inversion method
journal, January 2010

  • Kositsky, A. P.; Avouac, J. -P.
  • Journal of Geophysical Research, Vol. 115, Issue B3
  • DOI: 10.1029/2009JB006535

A Fortran 90 library for multitaper spectrum analysis
journal, August 2009


The effect of rupture complexity on estimates of source size
journal, February 1984


Along-strike rupture directivity of earthquakes of the 2009 L'Aquila, central Italy, seismic sequence
journal, August 2015

  • Calderoni, G.; Rovelli, A.; Ben-Zion, Y.
  • Geophysical Journal International, Vol. 203, Issue 1
  • DOI: 10.1093/gji/ggv275