Distinguishing high surf from volcanic long-period earthquakes

Geophysical Research Letters
By: , and 



Repeating long-period (LP) earthquakes are observed at active volcanoes worldwide and are typically attributed to unsteady pressure fluctuations associated with fluid migration through the volcanic plumbing system. Nonvolcanic sources of LP signals include ice movement and glacial outburst floods, and the waveform characteristics and frequency content of these events often make them difficult to distinguish from volcanic LP events. We analyze seismic and infrasound data from an LP swarm recorded at Pagan volcano on 12–14 October 2013 and compare the results to ocean wave data from a nearby buoy. We demonstrate that although the events show strong similarity to volcanic LP signals, the events are not volcanic but due to intense surf generated by a passing typhoon. Seismo-acoustic methods allow for rapid distinction of volcanic LP signals from those generated by large surf and other sources, a critical task for volcano monitoring.

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Publication type Article
Publication Subtype Journal Article
Title Distinguishing high surf from volcanic long-period earthquakes
Series title Geophysical Research Letters
DOI 10.1002/2013GL058954
Volume 41
Issue 4
Year Published 2014
Language English
Publisher American Geophysical Union
Contributing office(s) Volcano Hazards Program, Volcano Science Center
Description 8 p.
First page 1171
Last page 1178
Country Northern Mariana Islands
Other Geospatial Pagan Volcano
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