1958 Huslia earthquake
1958 Huslia earthquake is located in Alaska
Anchorage
Anchorage
Fairbanks
Fairbanks
1958 Huslia earthquake
UTC time1958-04-07 15:30:45
ISC event884131
USGS-ANSSComCat
Magnitude7.3 Ms
Depth6.0–7.0 km
Epicenter65°54′54″N 156°20′35″W / 65.915°N 156.343°W / 65.915; -156.343
TypeThrust (intraplate)
Areas affectedNorthern Alaska
Total damageMinor
Max. intensityVIII (Severe)
AftershocksYes
CasualtiesNone

The 1958 Huslia earthquake on April 7 struck an unusual part of Alaska, near the city of Huslia, about 415 km from Fairbanks. The Ms  7.3[1] 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 the state.[2] The earthquake was a result of compression of the crust due to the subduction of the Pacific Plate under the North American Plate.[3]

Earthquake

Further information: Intraplate earthquake

The earthquake was unusual for its location because it was situated in a geologically stable part of the North American Plate, more than 965 km from the 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.[4] The fault plane solution is either a shallow north-northwest dipping plane or a steep south-southwest dipping plane.[5] The earthquake was followed by two moderate aftershocks on April 8 and 12 respectively.[6][7]

Effects

Shaking from the earthquake reached VIII (Severe) on the Modified Mercalli intensity scale at its maximum within a radius of 40 to 50 miles. Meanwhile shaking in general was felt for an area of 150,000 square miles.[8] 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.[8]

See also

References

  1. ^ Hilary J., Fletcher; Douglas H., Christensen (1996). "A determination of source properties of large intraplate earthquakes in Alaska". Pure and Applied Geophysics. 146 (1): 21–41. Bibcode:1996PApGe.146...21F. doi:10.1007/BF00876668. S2CID 129277876.
  2. ^ "Preferred Magnitudes of Selected Significant Earthquakes" (PDF). US Geological Survey. 24 June 2013. Retrieved 2 Dec 2020.
  3. ^ "WHY EARTHQUAKES HAPPEN IN ALASKA". Alaska Earthquake Center. Retrieved 2 Dec 2020.
  4. ^ Reiser, Laura. "A Source Mechanism for the 7 April 1958 Huslia, Alaska Earthquake" (PDF). Third Keck Research Symposium in Geology.
  5. ^ 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.
  6. ^ "M 5.9 - northern Alaska". US Geological Survey. Retrieved 2 Dec 2020.
  7. ^ "M 5.9 - northern Alaska". US Geological Survey. Retrieved 2 Dec 2020.
  8. ^ a b 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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