Tuesday, April 24, 2007

Tsunami Caught in Action!

This past Saturday there was a 6.2 magnitude earthquake near Aysen Fjord in Southern Chile. The article describes the impacts of the earthquake, however someone also caught tsunami with 26 foot high waves on film! The tsunami wasn't caused by disturbances in the water column in response to shifting ocean floor (i.e. - see animation below for the cause of the Indonesian tsunami in 2004) but rather produced by a sub-aerial landslide terminating into the fjord! By sub-aerial I just mean it wasn't an submarine slide, which is also very common (i.e. - a famous example is the 1994 Skagway, Alaska tsunami).

The following video was downloaded and converted to flash (for faster loading) from here.



One of the most famous examples of a landslide induced tsunami is the 1958 Lituya Bay tsunami in Alaska. The wave produced by this landslide was 1,720 feet high! These stories "should" be of interest to residents of the Eastern United States given the potential (a, b, c) for landslides in the Canary Islands creating a 'mega-tsunami' (Ward and Day, 2001 & Wynn and Masson, 2003). Although controversial, the potential at least exists for a East Coast mega-tsunami... Not everyone will have time, but if you have 45 minutes to spare, you can watch video below summarizing the potential for East Coast mega-tsunamis. Some of the data presented has been argued as controversial so don't swallow the idea whole, but recognize the key word is "potential."

1 comments:

Miguel Vera said...

Hi John. I'm surprised to see your post about the Aysen event. I think you're the only english speaker geology blogger that mentioned it. What's interesting is that the seismic activity seems to be a mix of the Liquiñe-Ofqui fault movement and underground volcanic activity. Just so you know SERNAGEOMIN just published their study on the activity.

Anyway I'm glad I found your blog, I'll add a link in my own. Take care. Cheers.