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]
  Anchorage Fairbanks  | |
| UTC time | 1958-04-07 15:30:45 |
|---|---|
| ISC event | 884131 |
| USGS-ANSS | ComCat |
| Local date | April 7, 1958 |
| Magnitude | 7.3 Ms |
| Depth | 6.0–7.0 km |
| Epicenter | 65°54′54″N 156°20′35″W / 65.915°N 156.343°W |
| Type | Thrust (intraplate) |
| Areas affected | Northern Alaska |
| Total damage | Minor |
| Max. intensity | MMI VIII (Severe) |
| Aftershocks | Yes |
| Casualties | None |
Earthquake
editThe 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
editShaking 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
editReferences
edit- ^ 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.
- ^ "Preferred Magnitudes of Selected Significant Earthquakes" (PDF). United States Geological Survey. 24 June 2013. Retrieved 2 Dec 2020.
- ^ "WHY EARTHQUAKES HAPPEN IN ALASKA". Alaska Earthquake Center. Retrieved 2 Dec 2020.
- ^ Reiser, Laura. "A Source Mechanism for the 7 April 1958 Huslia, Alaska Earthquake" (PDF). Third Keck Research Symposium in Geology.
- ^ Thomas E. Moore, Julie A. Dumoulin (1994). Geologic studies in Alaska by the U.S. Geological Survey, 1994. United States: United States Geological Survey. p. 75.
- ^ "M 5.9 – northern Alaska". United States Geological Survey. Retrieved 2 Dec 2020.
- ^ "M 5.9 – northern Alaska". United States Geological Survey. Retrieved 2 Dec 2020.
- ^ 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.