Thursday, April 12, 2012

Science Nerd ~ Whole Lotta Shakin' Goin' On

I'm an nerdish earthquake watcher and I probably check the USGS List several times a day. I think it helps in these days of  "Apocalypse Doomsday" prophecies to learn what is normal geological activity for the earth and what is not.
 USGS Earthquakes in the World ~ Past Seven Days
 USGS Nifty New Real-Time Shake Map
USGS General Information and Lists State by State

This week there have been at least four big earthquakes in two days, as well as myriad large aftershocks, which caused  LiveScience to wonder if these are somehow connected:
It's possible, geophysicists say, that quakes off the coast of Oregon, Michoacan, Mexico, and in the Gulf of California ranging from magnitudes 5.9 to 6.9 on the Richter Scale had something to do with the large earthquake that struck near Indonesia. But the west coast quakes were fairly standard for their location. "The Earth is in constant motion," said Aaron Velasco, a geophysicist at the University of Texas, El Paso. "I wouldn't necessarily say it's unusual, but we will definitely be looking at these earthquakes to see if there's any link between them."
But why didn't the big 8.6 quake in Indonesia this week cause a huge Tsunami like the one back in 2004 that killed so many people and destroyed villages all around the Indian Ocean? Here we go, via The Conversation:
It was a “strike-slip earthquake”, which results in the ground moving with a more side-to-side motion, rather than an up-and-down motion. The side-to-side motion means there isn’t much up-and-down movement of the sea floor, so the water isn’t disturbed much. As a result, large tsunamis usually don’t form from slip-strike earthquakes.

Most people don't realize how many strong earthquakes there are in the world on any given day. The Pacific "Ring of Fire" is the main area, and nearly every day you'll see new quakes 5.0 and above : Honshu, Japan, where three major geological plates are still sliding under the ocean after the Tsunami disaster last year; Vanuatu and the Mollucca Sea north of Australia; Offshore Chile, which has been rumbling since 2010; Mexico, which has live volcanoes and where there's a "swarm" happening around Oaxaca as well as the Gulf of California right now; and Alaska, which shakes all the time but has limited effect on humans due to the small population of the state. California is the opposite with people packed into cities large and small, but  residents laugh off the danger and try to ignore fears about "The Big One." Then there are occasional bursts of activity around the Greek Isles, Italy, Africa, Greenland, Puerto Rico, and even the Virgin Islands due to Volcanoes.

And this is the fun part of watching the earthquake list ~ once you are familiar with the "normal" quake areas, you can easily spot the oddities. The Virginia quake last year that shifted the Washington Monument was fascinating and historical, being felt as far away as New Jersey. The strange quakes in Oklahoma, Arkansas, and Ohio that are possibly caused by gas-pipe "fracking" are unprecedented, and now those areas are hot-spots where there didn't used to be any quakes. But really earthquakes can happen in any state, so keep an eye on your shake map and be sure to report one if you feel it via the USGS interactive website!
Earthquake Map For the U.S. Heartland

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