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Hypothetical real-time GNSS modeling of the 2016 Mw 7.8 Kaikoura earthquake; perspectives from ground motion and tsunami inundation prediction

Brendan W. Crowell, Diego Melgar and Geng Jianghui
Hypothetical real-time GNSS modeling of the 2016 Mw 7.8 Kaikoura earthquake; perspectives from ground motion and tsunami inundation prediction (in 2016 Kaikoura earthquake, K. Berryman (editor), I. Hamling (editor), Anna E. Kaiser (editor) and T. Stahl (editor))
Bulletin of the Seismological Society of America (July 2018) 108 (3B): 1736-1745

Abstract

The 2016 Mw 7.8 Kaikoura earthquake is one of the most complex earthquakes in recent history, rupturing across many disparate faults with varying faulting styles. The complexity of this event has motivated the need for multidisciplinary geophysical studies to ascertain the underlying source physics in order to better inform earthquake hazards models in the future. However, events such as that in Kaikoura beg the question of how well (or how poorly) such earthquakes can be modeled automatically in real time and still satisfy the general public and emergency managers. To investigate this question, we perform a retrospective real-time Global Navigation Satellite System (GNSS) analysis of the Kaikoura earthquake with the G-FAST early-warning module. First, we perform simple point-source models of the earthquake using peak ground displacement scaling and a coseismic offset-based centroid moment tensor (CMT) inversion. We predict ground motions based on these point sources, as well as simple finite faults determined from source-scaling studies and validate against true recordings of peak ground acceleration. Second, we perform a slip inversion based upon the CMT fault orientations and forward-model near-field tsunami maximum expected wave heights to compare against available tide gauge records. We find remarkably good agreement between recorded and predicted ground motions when using a simple fault plane, with the majority of disagreement in ground motions being attributable to local site effects and directivity, not to earthquake source complexity. Similarly, the near-field tsunami maximum amplitude predictions match tide gauge records well. We conclude that, even though our models for the Kaikoura earthquake are devoid of rich source complexities, the CMT-driven finite fault is a good-enough average source and provides useful constraints for rapid forecasting of ground motion and near-field tsunami amplitudes.


ISSN: 0037-1106
EISSN: 1943-3573
Coden: BSSAAP
Serial Title: Bulletin of the Seismological Society of America
Serial Volume: 108
Serial Issue: 3B
Title: Hypothetical real-time GNSS modeling of the 2016 Mw 7.8 Kaikoura earthquake; perspectives from ground motion and tsunami inundation prediction
Title: 2016 Kaikoura earthquake
Author(s): Crowell, Brendan W.Melgar, DiegoGeng Jianghui
Author(s): Berryman, K.editor
Author(s): Hamling, I.editor
Author(s): Kaiser, Anna E.editor
Author(s): Stahl, T.editor
Affiliation: University of Washington, Department of Earth and Space Sciences, Seattle, WA, United States
Affiliation: GNS Science, Lower Hutt, New Zealand
Pages: 1736-1745
Published: 201807
Text Language: English
Publisher: Seismological Society of America, Berkeley, CA, United States
References: 38
Accession Number: 2018-094146
Categories: Environmental geologySeismology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sketch maps
S42°34'60" - S41°40'00", E173°00'00" - E174°04'60"
Secondary Affiliation: University of Oregon, USA, United StatesWuhan University, CHN, China
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Abstract, Copyright, Seismological Society of America. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201850
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