Flutterby™! : Tsunami

Next unread comment / Catchup all unread comments User Account Info | Logout | XML/Pilot/etc versions | Long version (with comments) | Weblog archives | Site Map | | Browse Topics


2011-03-11 22:57:48.181344+00 by Dan Lyke 4 comments

Y'all know that a big earthquake and huge tsunami hit Japan today. Aside from the massive destruction and at least hundreds killed, there are safety concerns at a nuclear power plant.

And, of course, those of us who live on the West Coast made conscious decisions about where we were going to be today. this summary of damage along the coast says:

Near the mouth of the Klamath River, three friends who had gathered to take photos were swept into the ocean. Two of the men made it back to shore, but the Coast Guard is using helicopters to help search for the third man.

What part of "tsunami"...?

A cool picture of what the wave looked like as it came ashore in Emeryville, and from the comments in that thread a video from a guy on the beach in Alameda videoing the draw-down ("I'm gonna run now") and video of the wave sweeping ashore from a high vantage point. Nothing like the devastation in Japan, but worth a little respect nonetheless.

And I want to get some further clarification on what this means, but the Vancouver Sun reports that the Japan coast shifted 2.4 meters and the earth's axis moved by inches. I wonder if our local resident favorite geographer would care to weigh in with a few words on what that sort of shift means for location...

[ related topics: Photography Movies Nature and environment Theater & Plays California Culture Earthquake Video Aviation - Helicopters ]

comments in descending chronological order (reverse):

#Comment Re: made: 2011-03-16 19:19:19.743868+00 by: Dan Lyke

NASA article about the axis shift:

The calculations also show the Japan quake should have shifted the position of Earth's figure axis (the axis about which Earth's mass is balanced) by about 17 centimeters (6.5 inches), towards 133 degrees east longitude. Earth's figure axis should not be confused with its north-south axis; they are offset by about 10 meters (about 33 feet).

#Comment Re: made: 2011-03-13 18:49:50.203359+00 by: spc476

Here's a report on just how prepared Japan was, and is in case of an earthquake.

#Comment Re: made: 2011-03-12 06:56:26.135204+00 by: ebradway

I hadn't realized that the Japanese coast had shifted that much. That must be why there's been so much chatter on the CrisisMap lists about reference systems and grids. Basically, it means that either a bunch of stuff needs to be re- surveyed or the entire grid needs to shift.

As for the Earth's axis moving, these things a cumulative and the reason we all upgrade reference systems every so often: NAD27 was adopted in 1927 but superseded by NAD84 in 1984.

Just peaked at Wikipedia. It looks like WGS84 has a mechanism for updating the geoid its based on. That is, the Earth is neither a sphere, nor an egg shape. It's actually a much more complex shape that is best calculated based on gravitation forces near the surface. This shape, the geoid, is updated regularly. The last update to WGS84 was in 2004. We are due for another. Perhaps this earthquake and the recent earthquakes in Chile and Haiti will spur a faster update. It does mean every GPS would need an software update as it's really just a few parameters in a mathematical model.

You really want to ask a geodesist this question.

And dig around on the USGS Earthquake site. Dan's met one of the guys who runs it. We flew kites together a few years ago!

#Comment Re: made: 2011-03-11 23:52:32.124746+00 by: Dan Lyke

Direct link to the Flickr page of the photo.