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Published March 16, 2019 | Supplemental Material + Published
Journal Article Open

Triggering of the Mw 7.2 Hawaii earthquake of May 4, 2018 by a dike intrusion

Abstract

A Mw 7.2 earthquake struck the south flank of Kilauea, Hawaii, on 4 May 2018, following a period of volcanic unrest. To investigate its relationship with the stress changes induced by prior tectonic and magmatic activity, we model the coseismic slip distribution, preintrusion deformation, and dike intrusion using geodetic, seismic, and tsunami observations. The décollement beneath the south flank was creeping seaward by ~25 cm/year. Diking started on 20 April and led to fissure eruption on 3 May. The magmatic activity and creep resulted in an onshore U‐shaped zone of stress unloading, fringed by an off‐shore zone of stress buildup that apparently guided the 2018 rupture. It takes only 20 to 35 years at the preintrusion rate to accumulate a moment deficit equivalent to the moment that was released in 2018. This event falls short of balancing the moment budget since the 1975 Mw 7.7 earthquake.

Additional Information

© 2019 American Geophysical Union. Received 22 NOV 2018; Accepted 15 FEB 2019; Accepted article online 21 FEB 2019; Published online 9 MAR 2019. Raw GPS data for coseismic rupture inversion were downloaded from UNAVCO (available at ftp://data‐out.unavco.org/pub/rinex/); GPS time series were provided by Nevada Geodetic Laboratory (available at ftp://gneiss.nbmg.unr.edu/rapids/tenv/). Strong motion and teleseimic waveforms were obtained through the Data Management Center of the Incorporated Research Institutions for Seismology. Original Sentinel‐1 interferograms were provided by the European Space Agency's Sentinel‐1 satellite. Tsunami records at tide gauge were collected from Global Sea Level Observing System. This research was partially funded by the National Science Foundation through grant EAR‐182185. The research by Z. L. was supported by the NASA Earth Surface and Interior focus area and carried out at the Jet Propulsion Laboratory (JPL), California Institute of Technology. A. G. was supported by an appointment to the NASA Postdoctoral Program at JPL, California Institute of Technology, administered by Universities Space Research Association through a contract with NASA, in collaboration with the Agenzia Spaziale Italiana. We thank R. Burgmann for discussions and Wanpeng Feng for sharing his code on calculation of Coulomb stress change. We are grateful to Gavin Hayes (the Editor), Yong Zhang, and an anonymous reviewer for their constructive reviews. Most of the figures in this paper were prepared using Generic Mapping Tools (Wessel et al. 2013).

Attached Files

Published - Chen_et_al-2019-Geophysical_Research_Letters.pdf

Supplemental Material - grl58675-sup-0001-2018gl081428-s01.docx

Supplemental Material - grl58675-sup-0002-2018gl081428-fs01.pdf

Supplemental Material - grl58675-sup-0003-2018gl081428-fs02.pdf

Supplemental Material - grl58675-sup-0004-2018gl081428-fs03.pdf

Supplemental Material - grl58675-sup-0005-2018gl081428-fs04.pdf

Supplemental Material - grl58675-sup-0006-2018gl081428-fs05.pdf

Supplemental Material - grl58675-sup-0007-2018gl081428-fs06.pdf

Supplemental Material - grl58675-sup-0008-2018gl081428-fs07.pdf

Supplemental Material - grl58675-sup-0009-2018gl081428-fs08.pdf

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Additional details

Created:
August 19, 2023
Modified:
October 20, 2023