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Global frequency of magnitude 9 earthquakes

Robert McCaffrey
Global frequency of magnitude 9 earthquakes
Geology (Boulder) (March 2008) 36 (3): 263-266


For decades seismologists have sought causal relationships between maximum earthquake sizes and other properties of subduction zones, with the underlying notion that some subduction zones may never produce a magnitude approximately 9 or larger event. The 2004 Andaman M (sub w) -9.2 earthquake called into question such ideas. Given multicentury return times of the greatest earthquakes, ignorance of those return times and our very limited observation span, I suggest that we cannot yet make such determinations. Present evidence cannot rule out that any subduction zone may produce a magnitude 9 or larger earthquake. Based on theoretical recurrence times, I estimate that one to three M9 earthquakes should occur globally per century, and the past half century with five M9 events reflects temporal clustering and not the long-term average.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 36
Serial Issue: 3
Title: Global frequency of magnitude 9 earthquakes
Author(s): McCaffrey, Robert
Affiliation: GNS Science, Lower Hutt, New Zealand
Pages: 263-266
Published: 200803
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 25
Accession Number: 2008-072120
Categories: Seismology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2008063
Illustration Description: illus. incl. sketch map
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200819
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