Last year the 50th anniversary of the Great Alaska Earthquake drew a lot of interest to the Gulf of Alaska’s coastal geology, and the mechanisms that caused the second largest quake ever recorded. In fact, the milestone attracted the membership of the Seismological Society of America to Alaska for the group’s annual meeting.
Rich Koehler is an earthquake geologist with the state’s Division of Geological and Geophysical Surveys in Fairbanks. He says the new guidebook can be used to educate planners, land mangers, engineers and scientists working in this seismically-active region.
“The abstracts in the volume were contributed by researchers around th3e world that came for the Seismological Society of America Conference in Anchorage last spring, and the field trip was sponsored by the International Geo-science Program. So they run a field trip every year, and we were lucky enough to have it in Alaska last year.”
Though filled with scientific abstracts, Koehler says it should be accessible for the non-scientist.
“Though we go into the detail of the science, but each field locality describes sort of what happened in 1964, so the layperson can get a grasp of what the effects were in certain areas. People can learn by flipping through it there’s lots of illustrations and photographs and things like that as well.”
And since it was produced during a seven-day field conference, Koehler says it’s a perfect companion for a field trip.
“So we have a guidebook series we produce here at GGS that we produce every time we do these big field trips. So this one was kind of special because we had a large group of international scientists all experts in their fields. It’s a great little guide to take on a tour. You can drive from Anchorage and go down to Seward and Whittier and take the ferry and go over to Cordova. So if you’re in any of those areas, this guidebook would provide you with figures and illustrations and texts to describe what you’re seeing.”
The book describes the work done to detect the evidence of prehistoric earthquakes on the scale of 1964. So, yes, the Big One has happened before, and it very likely will happen again in the future.
“Well, with the current state of the science, we have a recurrence interval of 300 to 800- or 900-years or so. So for an exact repeat of the 1964 earthquake we probably have some time, but that’s not to say you can’t have smaller earthquakes in the magnitude eight range or eight-plus that can rupture in that same patch, at any time.”
The guidebook is available for free download from the Alaska Division of Geological and Geophysical Surveys website, or you can order a hard copy for $16.