M7.1 November 30, 2018 Anchorage Earthquake

Science Center Objects

A magnitude 7.1 earthquake struck north of Anchorage, Alaska, on November 30, 2018, at 8:29 a.m. local time (17:29:28 UTC). 

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In the News

Evidence of turbidity currents in Eklutna Lake triggered by shaking during the 2018 Mw7.1 Anchorage earthquake

USGS scientists, working with researchers from the University of Ghent, probed the floor of Eklutna Lake, Anchorage Borough, Alaska, for evidence of turbidity currents triggered by strong shaking during the 2018 Mw7.1 Anchorage earthquake. In this photo, USGS scientist Peter Haeussler points to a dark layer at the top of a sediment core taken from the floor of Eklutna Lake. Research demonstrated that this dark layer, called a turbidite, was deposited on the lake floor after the 2018 earthquake. Field research took place in February 2019 when the lake was frozen, which allowed scientists to drill through the ice to collect 32 sediment cores. The deepest part of the lake exceeds 55 m (180 feet) (See SRL article by Van Daele et al., 2019, in press).
​​​​​​​(Credit: Rob Witter, USGS. Public domain.)

Symposium and Talks

  • 11/20/19:  Fireside Chat:  Did You Feel It?
  • 09/24-26/19: One Year Later: Symposium on the 2018 M7.1 Anchorage Earthquake
    • Thirty USGS scientists from around the country, including the Alaska Region and the Alaska Science Center, participated in the National Earthquake Hazards Reduction Program Alaska Earthquake Workshop, held in Anchorage, AK. This symposium, focused on the 2018 M7.1 Anchorage Earthquake and its consequences, and highlighted the research that has already occurred in the past year and will stimulate new investigations and collaborations to make the most of this learning opportunity. 

USGS Event page

Tectonic summary, maps and data.  The USGS event page has the most up-to-date information, and for estimates of casualties and damage, visit the USGS Prompt Assessment of Global Earthquakes for Response (PAGER) website.

Shakemap

Map showing ground motion and shaking intensity based on instrumental measurements of shaking along with information about local geology and the earthquake’s location and magnitude.

Did You Feel It?

Map of shaking intensity based on 15,000+ reports from citizens who experienced the earthquake.

Anchorage Office Building Shaking Visualizations

These videos presents a visualization of how the Frontier Building, Atwood Building and BP Building in Anchorage, Alaska, shook during the moment magnitude (Mw) 7.1 November 30, 2018, Anchorage, Alaska, earthquake. The buildings were instrumented by U.S. Geological Survey to obtain data to study its behavior and performance during strong shaking. Such data are useful in making decisions about improving the performance of this and similar buildings.

Credit for each video: Mehmet Çelebi, USGS (Public domain.)

Note that relative to the height of the building, the motions are magnified by a factor of 150 to show how the building deforms. Translational (back-and-forth) motion (dominant in the east-designated direction) and limited torsional (twisting) motions are observed.

An earlier video of the Frontier Building visualizing shaking during the Mw 7.1 January 24, 2016, Iniskin, Alaska, earthquake can be found at https://www.youtube.com/watch?v=A6EG7NXel9g.

Note that relative to the height of the building, the motions are magnified by a factor of 100 to show how the building deforms. Translational (back-and-forth) motion (more dominant in the East-designated direction) and limited torsional (twisting) motions are both observed, as well as limited beating effects (alternating cycles of generally increasing and decreasing levels of motion that occur when the structural damping of a building is low and when frequencies of translational and torsional motions are close).

An earlier video of the Atwood building visualizing shaking during the Mw7.1 January 24, 2016, Iniskin, Alaska, earthquake is available.

Note that relative to the height of the building, the motions are magnified by a factor of 150 to show how the building deforms. Translational (back-and-forth) motion (dominant in the east direction) and limited torsional (twisting) motions are observed. Please note that the 14-story BP Exploration Building is sparsely instrumented, having sensors at the ground, 8th, and 14th (roof) levels only (shown in the video as heavy black lines). Therefore, in developing the video, we used interpolation of displacements between the roof and 8th floor and between the 8th floor and ground level. As a result, in the visualization, only the displacements at the ground, 8th, and 14th (roof) levels should be considered accurate. The other level displacements are the result of interpolation.