The Loma Prieta earthquake of October 17, 1989: Introduction to the special issue

Journal Article · Sun Jul 01 00:00:00 EDT 1990 · Geophysical Research Letters (American Geophysical Union); (USA)

DOI:https://doi.org/10.1029/GL017i008p01177· OSTI ID:5981140

McNally, K; Ward, S N ^[1]

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1. Univ. of California, Santa Cruz (USA)

The southern Santa Cruz Mountains segment of the San Andreas fault that ruptured in the large (M{sub s}=7.1, M{sub w}=6.9) earthquake of October 17, 1989 (October 18, universal time) last slipped 84 years ago when it formed the southern terminus of the great 1906 break which extended from Cape Mendocino to San Juan Bautista. Being the most significant reactivation of a major fault segment in California during the modern instrumental era, the Loma Prieta earthquake has justifiably attracted considerable attention. It is, therefore, appropriate to devote a Special Section of Geophysical Research Letter (GRL) to the preliminary scientific findings about the quake. The Loma Prieta event was especially challenging. Unlike the textbook illustration of a right lateral fault, slip in this earthquake was not shallow nor uniform; indeed, rupture did not even reach the surface. More amazing still, a significant component of displacement on this supposed strike slip fault was vertical. As many pre-conceptions went up in smoke, many new questions materialized: How and where is strain energy stored along the fault Is the San Andreas beneath the Santa Cruz Mountains complicated, with several intersecting strands which break differently at different times How are lateral and vertical motion accommodated versus depth and time To what extent can a broad spectrum of proposed fault zone heterogeneities and structures be imaged Is the Loma Prieta failure characteristic for this section of the San Andreas and should it be grouped with the 1865 and 1906 events for hazard estimation Finally, just how predictable was the 1989 quake

• OSTI ID: 5981140
• Journal Information: Geophysical Research Letters (American Geophysical Union); (USA), Vol. 17:8; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
CALIFORNIA
EARTHQUAKES
RESEARCH PROGRAMS
DEPTH
EARTHQUAKE MAGNITUDE
FORECASTING
GEOLOGIC FAULTS
INFORMATION NEEDS
ROCK MECHANICS
RUPTURES
SEISMOLOGY
SLIP
DIMENSIONS
FAILURES
FEDERAL REGION IX
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
MECHANICS
NORTH AMERICA
SEISMIC EVENTS
USA
580000* - Geosciences