A Caltech Library Service

A single-force model for the 1975 Kalapana, Hawaii, Earthquake

Eissler, Holly K. and Kanamori, Hiroo (1987) A single-force model for the 1975 Kalapana, Hawaii, Earthquake. Journal of Geophysical Research B, 92 (B6). pp. 4827-4836. ISSN 0148-0227. doi:10.1029/JB092iB06p04827.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


A single force mechanism is investigated as the source of long-period seismic radiation from the 1975 Kalapana, Hawaii, earthquake (M_S = 7.1). The observed Love wave radiation pattern determined from the spectra of World-Wide Standard Seismograph Network and High Gain Long Period records at 100 s is two-lobed with azimuth, consistent with a near-horizontal single force acting opposite (strike ∼330°) to the observed displacement direction of the earthquake; this pattern is inconsistent with the expected double-couple pattern. Assuming a form of the force time history of a one-cycle sinusoid, the total duration of the event estimated from Rayleigh waves at two International Deployment of Accelerometers stations is approximately 180 s. The peak amplitude f_o of the time function is 1 × 10^(15) N from amplitudes of Love and Rayleigh waves. The interpretation is that the bulk of the seismic radiation was produced by large-scale slumping of a large area of the south flank of Kilauea volcano. The single force is a crude representation of the effect on the earth of the motion of a partially decoupled large slide mass. Using the mass estimated from the tsunami generation area (∼ 10^(15)–10^(16) kg), the peak acceleration of the slide block (0.1–1 m s^(−2)) inferred from the seismic force is comparable with the acceleration due to gravity on a gently inclined plane. The slump model for the Kalapana earthquake is also more qualitatively consistent with the large horizontal deformation (8 m on land) and tsunami associated with the earthquake, which are difficult to explain with the conventional double-couple source model. The single-force source has been used previously to model the long-period seismic waves from the landslide accompanying the eruption of Mount St. Helens volcano, and may explain other anomalous seismic events as being due to massive slumping of sediments or unconsolidated material and not to elastic dislocation.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle
Kanamori, Hiroo0000-0001-8219-9428
Additional Information:© 1987 by the American Geophysical Union. Paper number 6B6225. Received August 4, 1986; revised December 9, 1986; accepted December 18, 1986. We thank personnel at the Albuquerque Seismological Laboratory of the U.S. Geological Survey for preparing a tape of HGLP data upon request. Gordon Stewart originally collected the WWSSN records used in this study. We acknowledge conversations with James Moore and Richard Fiske and useful criticism by the JGR reviewers. This research was supported by National Science Foundation grants EAR-8313223, Earth Sciences Section, and ECE-8303647, Engineering Section. Contribution 4331, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California.
Funding AgencyGrant Number
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences4331
Issue or Number:B6
Record Number:CaltechAUTHORS:20141105-090319354
Persistent URL:
Official Citation:Eissler, H. K., and H. Kanamori (1987), A single-force model for the 1975 Kalapana, Hawaii, Earthquake, J. Geophys. Res., 92(B6), 4827–4836, doi:10.1029/JB092iB06p04827
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:51273
Deposited By: Tony Diaz
Deposited On:05 Nov 2014 17:10
Last Modified:10 Nov 2021 19:08

Repository Staff Only: item control page