Publication Date:
2020-12-14
Description:
On November 3, 2002, a moment-magnitude (Mw) 7.9 earthquake produced
340 km of surface rupture on the Denali fault and two related faults in central
Alaska. The rupture, which proceeded from west to east, began with a 40-km-long
break on a previously unknown thrust fault. Estimates of surface slip on this thrust
were 3-6 m. Next came the principal surface break, along 220 km of the Denali
fault. There, right-lateral offset averaged almost 5 m and increased eastward to a
maximum of nearly 9 m. Finally, slip turned southeastward onto the Totschunda
fault, where dextral offsets up to 3 m continued for another 70 km. This three-part
rupture ranks among the longest documented strike-slip events of the past two
centuries. The surface-slip distribution supports and clarifies models of
seismological and geodetic data that indicated initial thrusting followed by rightlateral
strike slip, with the largest moment release near the east end of the Denali
fault. The Denali fault ruptured beneath the Trans-Alaska oil pipeline. The
pipeline withstood almost 6 m of lateral offset, because engineers designed it to
survive such offsets based on pre-construction geological studies. The Denali
fault earthquake was typical of large-magnitude earthquakes on major
intracontinental strike-slip faults, in the length of the rupture, the multiple fault
strands that ruptured, and the variable slip along strike.
Description:
Published
Description:
565-578
Description:
open
Keywords:
Earth crust
;
earthquakes
;
faulting
;
slip
;
pipelines
;
Denali fault
;
Susitna Glacier fault
;
Totschunda fault
;
Surface rupture
;
November 3, 2002 M7.9 earthquake
;
Alaska
;
04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Format:
1464275 bytes
Format:
application/pdf
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