Did it, or didn’t it ?

On 30 November 2018, at 17:29 UTC, a magnitude 7.0 earthquake hit South Central Alaska (see USGS Earthquake Catalog). The earthquake’s hypocenter was located at about 16 km north of Anchorage, and at a depth of 47 km.

Did this earthquake produce an event deposit (i.e. turbidite) in nearby Eklutna Lake, or not ? And if it did, what were its characteristics. This information is of key importance to calibrate and understand the sedimentary record of Eklutna Lake… similar turbidites, with similar characteristics, deeper in the sedimentary record could then be interpreted as resulting from similar types of earthquakes.

In order to verify if an event deposit was formed… Dr. Maarten Van Daele and Koen De Rycker went on a fast-response intervention coring survey in Alaska. In cooperation with our colleagues from the USGS (Peter Haeussler and Rob Witter) they collected 33 sediment cores in 2 days from the frozen surface of Eklutna Lake.

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If you want to know how sediment cores are taken from a frozen lake… watch this short YouTube movie

And some windy conditions on the second coring day…

 

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