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Published June 1, 2010 | Published + Supplemental Material
Journal Article Open

Effects of Kinematic Constraints on Teleseismic Finite-Source Rupture Inversions: Great Peruvian Earthquakes of 23 June 2001 and 15 August 2007

Abstract

Two great underthrusting earthquakes that occurred along the coast of Peru in 2001 and 2007 involve spatiotemporal slip distributions that differ from the predominantly unilateral or bilateral rupture expansion of many great events. Commonly used finite-source rupture model parameterizations, with specified rupture velocity and/or short duration of slip at each grid point applied to the seismic data for these two events, lead to incorrect slip-distributions or inaccurate estimation of rupture velocities as a result of intrinsic kinematic constraints imposed on the model slip distributions. Guided by large aperture array back projections of teleseismic broadband P-wave signals that image slip locations without imposing a priori kinematic constraints on the rupture process, we exploit the availability of large global broadband body and surface wave data sets to consider the effects of varying the kinematic constraints in teleseismic finite-source waveform inversions. By allowing longer than usual rupture durations at each point on the fault using a flexible subfault source-time function parameterization, we find that the anomalous attributes of the 2001 and 2007 Peru earthquake ruptures are readily recognized and accounted for by compound rupture models. The great 23 June 2001 (M_w 8.4 8.4) earthquake involved an initial modest-size event that appears to have triggered a much larger secondary event about 120 km away that developed an overall slip distribution with significant slip located back along the megathrust in the vicinity of the initial rupture. The great 15 August 2007 (M_w 8.0 8.0) earthquake was also a composite event, with a modest size initial rupture followed by a 60-sec delayed larger rupture that initiated 50–60 km away and spread up-dip and bilaterally. When back projections indicate greater rupture complexity than captured in a simple slip-pulse-type rupture model, one should allow for possible long-subfault slip-duration or composite triggered sequences, and not overly constrain the earthquake slip distribution.

Additional Information

© 2010 Seismological Society of America. Manuscript received 2 September 2009. We thank the Global Seismic Network, Federation of Digital Seismic Networks, EarthScope USArray operators, and the IRIS Data Management System for providing access to the bountiful, well-calibrated broadband seismic recordings used in this article. We have benefited from discussions with Chen Ji concerning parameterizations for finite-source inversions. We thank Gavin Hayes for a review and two anonymous reviewers for their helpful comments. Anthony Sladen kindly provided a preprint in advance of publication. This article is supported by NSF grants EAR0453884 and EAR0635570 (TL) and USGS Award Number 05HQGR0174 (CJA).

Attached Files

Published - Lay2010p10212B_Seismol_Soc_Am.pdf

Supplemental Material - FigureS1.LAHK_2001_iterative_fits.png

Supplemental Material - FigureS2.LAHK_2001_Vr2.5_2.2.9_fits.png

Supplemental Material - FigureS3.LAHK_2001_doublet.png

Supplemental Material - FigureS4.LAHK_2007_iterative_fits.png

Supplemental Material - FigureS5.LAHK_2007_Vr0.9.2.5.2.5.5.fits.png

Supplemental Material - FigureS6.LAHK_2007_doublet.png

Supplemental Material - MovieS01_2001_BP.fixed.mov

Supplemental Material - MovieS02_2001_BP_variable.mov

Supplemental Material - MovieS03_2007_BP_fixed.mov

Supplemental Material - MovieS04_2007_BP_variable.mov

Supplemental Material - MovieS05_StaDistWeight.mov

Supplemental Material - MovieS06a_2001.Vr2.5.2.2.9.slip.mov

Supplemental Material - MovieS06b_2001.Vr2.5.2.2.9.mr.mov

Supplemental Material - MovieS07a_2001.Vr2.5.4.4.13.slip.mov

Supplemental Material - MovieS07b_2001.Vr2.5.4.4.13.mr.mov

Supplemental Material - MovieS08a_2001.composite.slip.mov

Supplemental Material - MovieS08b_2001.composite.mr.mov

Supplemental Material - MovieS09a_2007.Vr0.9.2.5.2.5.slip.mov

Supplemental Material - MovieS09b_2007.Vr0.9.2.5.2.5.mr.mov

Supplemental Material - MovieS10a_2007.Vr3.11.3.5.3.5.22.slip.mov

Supplemental Material - MovieS10b_2007.Vr3.11.3.5.3.5.22.mr.mov

Supplemental Material - MovieS11a_2007.composite.slip.mov

Supplemental Material - MovieS11b_2007.composite.mr.mov

Supplemental Material - MovieS12_2001_data_synthetics.mov

Supplemental Material - MovieS13_2007_data_synthetics.mov

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FigureS4.LAHK_2007_iterative_fits.png
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Additional details

Created:
August 23, 2023
Modified:
October 20, 2023