1958 Huslia earthquake

The Northern Alaska earthquake of 1958 struck in an unusual part of state, near the small city of Huslia, about 415 km from Fairbanks. The mb 7.3 earthquake is one of two magnitude 7.0 or greater earthquakes recorded north of 65° latitude, the other being the 1933 Baffin Bay earthquake, and is one of the strongest earthquakes within the interior of Alaska.[1] The earthquake was a result of compression of the crust due to the subduction of the Pacific Plate under the North American Plate.[2]

1958 Huslia, Alaska earthquake
Anchorage
Fairbanks
UTC time1958-04-07 15:30:45
ISC event884131
USGS-ANSSComCat
Local date
Local time
Magnitude7.3 mb
Depth6.0-7.0 km
Epicenter65.915°N 156.343°W / 65.915; -156.343
TypeThrust (intraplate)
Areas affectedNorthern Alaska
Total damageMinor
Max. intensityVIII (Severe)
AftershocksYes
CasualtiesNone

Earthquake

see Intraplate earthquake

The earthquake was unusual for its location because it was situated in a geologically stable part of the North American Plate, more that 965 km from the Alaska-Aleutian Subduction Zone, the nearest plate boundary. There are no known visible fault traces in the immediate vicinity of the earthquake other than a thrust fault under the Brooks Range and another strike-slip feature known as the Kaltag Fault. The Koyukuk Basin consists of accretion of volcanic arcs from the Middle Jurassic to Early Cretaceous. P-wave analysis suggests that the earthquake was a result of thrust faulting at a depth of 6 km.[3] The fault plane solution is either a shallow north-northwest dipping plane of steep south-southwest dipping plane.[4] The earthquake was followed by two moderate aftershocks on April 8 and 12 respectively.[5][6]

Effects

Shaking from the earthquake reached VIII on the Mercalli intensity scale at its maximum within a radius of 40 to 50 miles while shaking in general was felt for an area of 150,000 square miles.[7] Ice cracks and liquefaction was reported for an area of 400 square miles. Pressure ridges, lakes thawing, and craters 20 feet across and 6 feet deep were reported during a survey. In Huslia, minor damage to roofs and foundations. An old building in Stevens Village was declared unsafe after it was seen that poles supporting its roof had split and broken. Ice from a frozen river cracked and ground fissures opened at Tanana. More damage was reported in other towns.[7]

See also

References
  1. "Preferred Magnitudes of Selected Significant Earthquakes" (PDF). US Geological Survey. 24 June 2013. Retrieved 2 Dec 2020.
  2. "WHY EARTHQUAKES HAPPEN IN ALASKA". Alaska Earthquake Center. Retrieved 2 Dec 2020.
  3. Reiser, Laura. "A Source Mechanism for the 7 April 1958 Huslia, Alaska Earthquake" (PDF). Third Keck Research Symposium in Geology.
  4. Thomas E. Moore, Julie A. Dumoulin (1994). Geologic studies in Alaska by the U.S. Geological Survey, 1994. United States: US Geological Survey. p. 75.
  5. "M 5.9 - northern Alaska". US Geological Survey. Retrieved 2 Dec 2020.
  6. "M 5.9 - northern Alaska". US Geological Survey. Retrieved 2 Dec 2020.
  7. Jerry L. Coffman, Carl A. von Hake (1977). EARTHQUAKE HISTORY OF THE UNITED STATES. United States: U.S. DEPARTMENT OF COMMERCE. pp. 116–117.
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