Seismic potential of the Queen Charlotte-Alaska-Aleutian seismic zone
- Geological Survey, Denver, CO (United States)
- Columbia Univ., Palisades, NY (United States)
The 5,000 km long Queen Charlotte-Alaska-Aleutian seismic zone is subdivided into 17 unequally sized segments. The 17 segments are chosen to represent areas likely to be ruptured by characteristic earthquakes. This term usually implies repeated breakage of a plate boundary segment by either a large or great earthquake, whose source dimensions remain consistent from cycle to cycle. Formal computations of the conditional probabilities for future large and great earthquakes in the 17 segments of the Queen Charlotte-Alaska-Aleutian seismic zone are based on the following data sets and findings: (1) recurrence intervals from historic and geologic data; (2) direct recurrence time estimates based on rates of relative plate motion and the size or displacement of the most recent characteristic event in each segment; and (3) the application of a lognormal distribution of recurrence times for large and great earthquakes. Results of these computations indicate seven areas that have high (i.e., {ge} 60%) conditional probabilities for the recurrence of either large or great earthquakes within the next 20 years (1988-2008). These areas include Cape St. James, Yakataga, the Shumagin Islands, Unimak Island, and the Fox, Delarof, and Near Islands segments of the Aleutian arc. When a shorter time interval is considered (1988-1998), those segments more likely to rupture in large (M{sub S} 7-7.7) rather than great earthquakes have a high conditional probability. These areas include the Unimak, Fox, and Delarof Islands segments. The largest uncertainties in these forecasts stem from the short historic record (providing a single recurrence time estimate for some segments, or widely varying estimates for others); from the unknown importance of aseismic slip; and from a vague definition of characteristic earthquake size. In fact, characteristic earthquake size may not be a time-invariant quantity.
- DOE Contract Number:
- FG02-84ER13221
- OSTI ID:
- 5073853
- Journal Information:
- Journal of Geophysical Research; (United States), Vol. 95:B3; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
Similar Records
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Related Subjects
EARTHQUAKES
RISK ASSESSMENT
GULF OF ALASKA
ALASKA
ALEUTIAN ISLANDS
BRITISH COLUMBIA
COASTAL REGIONS
EARTHQUAKE MAGNITUDE
FORECASTING
GEOLOGY
HISTORICAL ASPECTS
PLATE TECTONICS
PROBABILITY
RUPTURES
TIME DEPENDENCE
CANADA
DEVELOPED COUNTRIES
FAILURES
FEDERAL REGION X
ISLANDS
NORTH AMERICA
PACIFIC OCEAN
SEAS
SEISMIC EVENTS
SURFACE WATERS
TECTONICS
USA
580000* - Geosciences