Great Alaskan Earthquakes
-
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.
-
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.
-
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…
-
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…
-
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…
-
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…
-
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!).
-
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.
-
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…
