2001 Nisqually earthquake

2001 Nisqually earthquake
Date February 28, 2001
Magnitude 6.8 Mw
Depth 52 kilometers (32 mi)
Epicenter 47°09′N 122°44′W / 47.15°N 122.73°WCoordinates: 47°09′N 122°44′W / 47.15°N 122.73°W
Areas affected United States, Canada
Casualties 1 dead, about 400 injuries

The Nisqually earthquake (also commonly referred to as "The Ash Wednesday Quake") was an intraslab earthquake, occurring at 10:54 am PST (18:54 UTC) on February 28, 2001. One of the largest recorded earthquakes in Washington state history, it measured 6.8 on the moment magnitude scale and lasted approximately 45 seconds. The epicenter of the earthquake was Anderson Island, about 17 km (11 mi) northeast of Olympia. The focus was at a depth of 52 km (32 mi). Tremors were felt as far away as Scio, Oregon, across the border in Vancouver, British Columbia, Canada, and 175 mi (282 km) east in Pasco, Washington. There were also reports that it was felt as far away as Spokane, Washington and Sandpoint, Idaho.[1]

The quake caused some property damage in Seattle and surrounding areas. Although there were no reports of deaths directly from the earthquake, local news outlets reported that there was one death from a heart attack at the time of the earthquake.[2]

Geological origins

The Puget Sound area, where this earthquake occurred, is prone to deep earthquakes due to the Juan de Fuca tectonic plate's subduction under the North American Plate at 3.5 to 4.5 cm. a year[3] as part of the Cascadia subduction zone, which causes stress in the former as it sinks into the mantle. As an intraslab earthquake, it was produced by a change in volume as rock changed from one form to another. Similar significant earthquakes occurred in the same general region on April 29, 1965 (magnitude 6.5, depth 63 km (39 mi)), and April 13, 1949 (magnitude 7.1, depth 53 km (33 mi)).

Damage and effects

A large van was crushed by earthquake debris in a Seattle parking lot.

About 400 people were injured.[2][4] Most of the property damage occurred very near the epicenter or in unreinforced concrete or masonry buildings, such as those in the First Hill, Pioneer Square and Sodo neighborhoods of Seattle. The Trinity Parish Church on First Hill was severely damaged.[5] The air traffic control tower at Sea-Tac Airport was heavily damaged during the quake; it has since been replaced with a more earthquake-resistant tower. The quake splintered a buttress under the dome of the capitol building in Olympia, but previous earthquake-resistance work prevented more serious harm to the building.[6] Additionally, the earthquake caused power outages in downtown Seattle.[7] The U.S. Military's Ft. Lewis and McChord Air Force Base received damage in the quake. There was very slight damage in Victoria, British Columbia.[8]

The Fourth Avenue Bridge in Olympia was destroyed.

Following the quake, many buildings and structures in the area were closed temporarily for inspection. This included several bridges, all state offices in Olympia, and Boeing's factories in the Seattle area. Various schools in the state also closed for the day. The Fourth Avenue Bridge in downtown Olympia was heavily damaged due to the quake and was later torn down and re-built.[9][10] In Seattle, the Alaskan Way Viaduct and its seawall were damaged, forcing the viaduct to close for emergency repairs and ultimately factoring into the decision to replace the viaduct entirely.[11]

Impact on natural area

Named after the Nisqually Delta, this earthquake hit the southern end of Puget Sound causing damage to the ports of Seattle and Tacoma.[12][13] In the month following the earthquake, the NOAA and USGS assembled a team to map the bathymetry of the deltas near the epicenter of the earthquake. This revealed multiple submarine failures on the Puyallup and Duwamish delta fronts. In other areas liquefaction, sand boils, landslides, and soil slumping occurred.[12] Liquefaction was also determined to be a main contributor to increased stream flows. With multiple stream gages collecting data before and after the earthquake there was a regular pattern of higher increased stream flow around areas where liquefaction occurred.[14] The earthquake did also go through a wildlife refuge causing liquefaction in the soil and damage to the buildings within. It also startled birds which may have caused some to move from the area but besides that, caused little harm to the wildlife.[15]

Effect on businesses

The earthquake caused approximately $305 million of insured losses and a total of $2 billion worth of damage in the state of Washington. The area was declared a natural disaster area by president George W. Bush and was therefore able to receive federal recovery assistance the day after the quake. The number of businesses in the heavily affected region was relatively small.[16] At least 20% of businesses surrounding the heavily affected area took direct losses from the earthquake while 2% had direct losses of over $10,000. None of these businesses received money for direct damage from federal aid or insurance.[16] Many businesses did not receive any aid at all. Those that did receive aid had no help with indirect losses. Indirect losses varied from inventory or data corruption, disruption in the workplace, productivity, etc. Data and inventory losses were possibly the most damaging, especially for retail stores. Retail stores lost inventory from the earthquake as well as people's interest for a period of time after the quake. One of the vital elements to prevent damage and injury were well structured buildings. This can prevent the loss of life as well as inventory.[16] Businesses that did not sustain very much damage also gained a sense of security that may be unreliable as the moment magnitude was high but the hypocenter was deep under the earth. This earthquake was a 6.8 moment magnitude that caused $2 billion damage while the Northridge earthquake was a 6.7 moment magnitude, but caused more than $20 billion worth of damage as the hypocenter of the Northridge Earthquake was much shallower and closer to the surface of the earth.[16][17]

Response

A year after the earthquake a rapid response plan was developed. The region realized how they avoided a potential extremely damaging catastrophe. Many businesses, organizations, hospitals, etc. were asked to sign a regional disaster plan. This would allow disaster relief teams to locate and aid places much faster than before. It would also be able to direct limited resources to places with greatest immediate need.[18][19]

See also

Wikimedia Commons has media related to 2001 Nisqually earthquake.

References

  1. ↑ Dewey, James W.; Margaret G. Hopper, David J. Wald, Vincent Quitoriano, and Elisabeth R. Adams (2002). Intensity Distribution and Isoseismal Maps for the Nisqually, Washington, Earthquake of 28 February 2001. U.S. Geological Survey. ISBN 9781428960961. Retrieved August 15, 2009.
  2. ↑ 2.0 2.1 "A Comparison of the February 28, 2001, Nisqually, Washington, and January 17, 1994, Northridge, California Earthquakes". Southern California Earthquake Center. Retrieved May 16, 2012.
  3. ↑ Peter W. McDonough (ed.). The Nisqually, Washington Earthquake of February 28, 2001. Reston, VA: ASCE, TCLEE. ISBN 9780784406151.
  4. ↑ Susan Wyatt (February 28, 2011). "10th anniversary of Nisqually earthquake". King 5 News. Retrieved May 16, 2012.
  5. ↑ Highland, Lynn M. (2002). An Account of Preliminary Landslide Damage and Losses Resulting from the February 28, 2001, Nisqually, Washington, Earthquake. U.S. Geological Survey. Retrieved August 15, 2009.
  6. ↑ David Postman (March 5, 2001). "Capitol did 'remarkably well'". The Seattle Times. Retrieved 2012-05-16.
  7. ↑ Linn, Allison (February 28, 2001). "Bill Gates speech interrupted by quake". The Associated Press. Retrieved March 30, 2007.
  8. ↑ Earthquakes Canada – Report (2001-02-28). Accessed January 23, 2009.
  9. ↑ "Fourth Avenue bridge: Bridge over rubbled water". The Olympian. 2002. Retrieved July 30, 2008.
  10. ↑ "Quake Capsules-Fourth Avenue Bridge". The Olympian. September 2, 2001. Retrieved July 30, 2008.
  11. ↑ "About the Alaskan Way Viaduct and Seawall". WSDOT. Retrieved 2012-05-16.
  12. ↑ 12.0 12.1 Nisqually Basin Bibliography: Science, Resource Management, Land Use, and Public Policy.
  13. ↑ A Comparison of the February 28, 2001, Nisqually, Washington, and January 17, 1994, Northridge, California Earthquakes.
  14. ↑ Streamflow response to the Nisqually earthquake.
  15. ↑ Earthquake Rattles Nisqually Refuge.
  16. ↑ 16.0 16.1 16.2 16.3 "Effects of the 2001 Nisqually Earthquake on Small Businesses in Washington State".
  17. ↑ Resilient Washington State
  18. ↑ On Nisqually Quake anniversary, region set to adopt rapid response pact; County repairs damage
  19. ↑ The Nisqually, Washington, Earthquake of February 28, 2001.

External links