Great Alaskan Earthquakes Archives - State of the Planet

New Images From Under Alaska Seafloor Suggest High Tsunami Danger

Scientists probing under the seafloor off Alaska have mapped a geologic structure that they say signals potential for a major tsunami in an area that normally would be considered benign.

by |July 31, 2017

Learning from Slow-Slip Earthquakes

Off the coast of New Zealand, there is an area where earthquakes can happen in slow-motion as two tectonic plates grind past one another. These slow-slip events create an ideal lab for studying fault behavior along the shallow portion of subduction zones.

by |December 15, 2016

Returning From Sea to Dutch Harbor

At 6:30 am on August 5, the R/V Langseth pulled into port in Dutch Harbor, marking the end of our very successful research cruise. Our steam into port from our study area involved a trip through Unimak pass and beautiful views of Aleutian volcanoes, including majestic Shishaldin. Many things are required to make a research… read more

by |August 8, 2011

Swimming in Data Offshore Alaska

Although we still have ~3 days of data collection aboard the R/V Langseth to go before we pull in our equipment and head for port, we are already drowning in beautiful seismic data. Following each pulse from the air gun array, the two 8-km-long streamers listen for returning sound waves for 22 seconds. This is… read more

by |July 31, 2011

Boring Days at Sea are a Blessing

For the last nine days, we have been underway acquiring seismic reflection data to study a plate tectonic boundary offshore Alaska with the R/V Marcus G. Langseth. Now that the initial excitement of deploying all of our seismic gear and watching the first sound waves arrive on our two 8-km-long streamers has faded, we have… read more

by |July 24, 2011

Collecting Data Offshore Alaska, But Just Barely

One of the core objectives of our project is to image the part of the plate tectonic boundary that locks up and then ruptures to produce great earthquakes. To examine deep parts of the interface between the Pacific plate and the North American plate in the Aleutian subduction zone, we need to go as close to the coast as possible. This is easier said than done.

by |July 18, 2011

Unspooling Miles of Seismic Streamer Near the Shumagin Islands

On July 11, we marked the successful completion of the first phase of our project and embarked on the second. Part 1 involved deploying ocean bottom seismometers and recording air-gun-generated sound waves. We successfully retrieved all of the OBS’s, and the data that they recorded look very exciting at first blush (and contain some surprises!).

by |July 14, 2011

Summoning ocean bottom seismometers from the deep

After leaving our seismometers on the seafloor offshore Alaska for a few days to record sound waves generated by the air guns of the R/V Langseth, we returned to collect them. The recovery of OBS always involves a certain amount of suspense.

by |July 8, 2011

Deploying Ocean Bottom Seismometers off Alaska

On July 2, we finished deploying over twenty ocean-bottom seismometers as a part of our marine expedition to study a major tectonic boundary offshore Alaska. Ocean bottom seismometers (OBS’s) are autonomous instruments that sit on the seafloor and record sound waves traveling through the earth and the water. Floats made from glass balls and syntactic… read more

by |July 4, 2011

Heading to Sea off Alaska Aboard the R/V Langseth (at last)

Yesterday evening, we left Kodiak aboard the R/V Marcus G. Langseth and began our 38-day-long research cruise offshore Alaska. As we left port, we were treated to clear skies, calm seas and spectacular views of Kodiak – dark grey mountains tipped with snow emerging from the lush green landscape. Although Kodiak offered beautiful sights and… read more

by |June 30, 2011