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Recovering analog-tape seismograms from the 1980 Mount St. Helens pre-eruption period

Stephen D. Malone
Recovering analog-tape seismograms from the 1980 Mount St. Helens pre-eruption period
Seismological Research Letters (May 2020) 91 (3): 1430-1440


Mount St. Helens in Washington State erupted violently (Volcano Explosivity Index = 5) on 18 May 1980. During the previous two months, intense seismic activity at the volcano was recorded by a combination of continuous analog-tape recordings, paper drum recordings, and a recently installed triggered digital event computer system. Because of the technological constraints of the time, the digital data available cover only a little more than 1% of the two-month period. The paper drum records only exist for a few of the seismic stations and are also quite incomplete. However, the analog-tape data from some stations is near complete for almost the whole two months. During the period 2005-2014, these old analog tapes were recovered from storage and digitized to generate standard digital data for archiving at the Incorporated Research Institutions for Seismology Data Management Center. This recovery process was long and complicated but, for the most part, was fairly successful. Although the quality of these recovered data is nowhere near as good as modern digital seismograms, this dataset does provide a near-continuous record of the significant seismic sequence that led up to the major volcanic eruption. It includes the large variety of seismic signals from different types of volcanic earthquakes and harmonic tremor and should be a valuable resource for those studying volcanic seismicity.

ISSN: 0895-0695
EISSN: 1938-2057
Serial Title: Seismological Research Letters
Serial Volume: 91
Serial Issue: 3
Title: Recovering analog-tape seismograms from the 1980 Mount St. Helens pre-eruption period
Author(s): Malone, Stephen D.
Affiliation: University of Washington, Department of Earth and Space Sciences, Seattle, WA, United States
Pages: 1430-1440
Published: 202005
Text Language: English
Publisher: Seismological Society of America, El Cerrito, CA, United States
References: 8
Accession Number: 2020-070544
Categories: Seismology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, sketch map
N46°00'00" - N47°00'00", W122°30'00" - W121°00'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute. Abstract, Copyright, Seismological Society of America. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 202020
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