Blog Post #4: Earthquakes

New Madrid Seismic Zone

Even though there aren’t any visible plate boundaries in the middle of the United States, there is evidence of earthquakes occurring in the area. There are records of earthquakes occurring in 1811 and 1812 that were felt from Mexico to Canada. There is proof showing that those years were not the first time that earthquakes occurred there. A PBS NOVA video explains how stalagmites in caves prove that earthquakes did in fact occur. The rings are not counted as tree rings are counted. Instead the age of the layers are analyzied with chemicals. The stalagmites show evidence of violent earthquakes.

The ground in New Madrid, Missouri is actually an epicenter of the most active seismic zone to the east of the Rocky Mountains. This is the New Madird Seismic Zone, as a CUSEC article. The NMSZ is definitely a threat to the United States, that most people are not even aware about. An earthquake could strike at any time.

The Missouri Department of Natural Resources stated that “Due to the harder, colder, drier and less fractured nature of the rocks in the earth’s crust in the central United States, earthquakes in this region shake and damage an area approximately 20 times larger than earthquakes in California and most other active seismic areas.” This means that if an earthquake occurred they would be far worse than the ones we hear about happening at the San Andreas Fault.

One interesting theory for why the NMSZ is there sense is that the region lays over an ancient wound deep in the earth’s crust. It is thought that plates that were being pulled apart by tectonic forces suddenly stoped moving apart from each other. This “failed rift” created a weak spot in the crust which could be causing this seismic activity and occasional earthquakes.

Sources:

http://www.pbs.org/wgbh/nova/earth/earthquakes-midwest.html

http://www.cusec.org/earthquake-information/new-madrid-seismic-zone.html

http://www.dnr.mo.gov/geology/geosrv/geores/techbulletin1.htm

Blog Post #3: Glaciers

Greenland Melting

Greenland has become a symbol of global warming as the massive ice sheet that covers it is melting at a much faster rate. The Greenland ice sheet extends over 1000 miles, which is over 80% of the landmass of Greenland. It is melting at an unprecedented rate and as it melts, the edges start to break apart and fall into the water. Crashes can be heard nearby as the chunks of ice fall into the water. 10% of the world’s fresh water is frozen in Greenland, which is enough to raise sea level 23 feet globally. This is where the “global meltdown” begins.

According to a UK newspaper article in The Telegraph, an “area of ice three times the size of Manhattan Island” broke off between July 28^th and August 5^th in 2010. This photo shows the massive chunk breaking off.

As scary as it may seem to live in Greenland, there is a population of about 56 thousand.  What may be even more shocking is that the melting is beneficial to residents of Greenland. The documentary I Heart Global Warming explains how new areas of land are being uncovered due to the warming temperatures. This is exposing land that can now be explored. There are economic benefits of the melting because of all of the oil, gas, and minerals that can now be found. They are finding precious metals in the ice. There has even been success with selling bottled glacial melt water.

An article on thinkprogress.org explains how researchers are finding that “even if you don’t have record-breaking highs, as long as warm temperatures persist you can get record-breaking melting because of positive feedback mechanisms.” This cycle of warming and melting is very difficult to halt. The I Heart Global Warming documentary concludes with a powerful statement: “We’ve awakened a giant. And whatever we did to cause this, there’s no turning back. There’s no more preventing it. Maybe we can slow it down- we can still blunt its force. But it’s coming.”

Sources:

http://www.telegraph.co.uk/earth/earthnews/7941035/Ice-sheet-in-Greenland-melting-at-record-rate.html

http://www.hulu.com/watch/113347/vanguard-i-heart-global-warming

http://thinkprogress.org/romm/2011/10/24/351570/greenland-ice-sheet-melting-warming/