Earthquakes

Lithosphere: Earthquakes in Canada
You don’t need to be a geophysicist to hold a fascination for earthquakes. We have had and continue to have many earthquakes in Canada, and the effects of the lithosphere’s Pacific Plate are seen not far from Calgary where mild earthquake activity has been measured. Many seismograph stations are located throughout Canada, including at Edmonton and Wateron Lake. In Alberta and eastern BC we have several earthquakes per month, with some of them reported as having been felt. Areas of recent nearby activity (April and May 2007) include Dawson Creek BC and Jasper AB.

Here are some interesting links:
• Earthquakes 1600-2006 in Canada
• Earthquakes 1600-2006 in Canada
• Top 10 earthquakes in Canada
• The Magnitude 7.2 1929 "Grand Banks" earthquake and tsunami
• Overview Canadian earthquakes

The Joshua Tree Earthquake

On October 16, 1999 at 2:46 a.m. in Los Angeles, Karen was awakened at 3 am by the magnitude 7.1 Joshua Tree earthquake that occurred over a hundred miles away in the Joshua Tree National Park region. “Earthquakes are scientifically interesting except perhaps when you’re in one. With the hotel shaking, the windows rattling, and the water sloshing out of the pool, my first thoughts were more on how we were going to get out of there and less about the science!”

Aerial View of strike-slip fault at Joshua Tree

• 1999 Hector Mine earthquake

Measuring Earthquakes
“In the 1930's, C.F. Richter devised a way measure the magnitude of an earthquake using an instrument called a seismograph to measure the speed of ground motion during an earthquake. Geologists discovered that the energy released in an earthquake goes up with magnitude faster than the ground speed by a factor of 32.
If you do the calculations, you'll see that a magnitude 7 earthquake has 32 times more energy than a magnitude 6 and almost 1,000 times more energy than a magnitude 5 earthquake! This doesn't mean there will be 1,000 times more shaking at your house. Large earthquakes last longer and spread their energy out over a much larger area.”

Haiti Earthquake Was Forecast
A magnitude 7.0 earthquake struck near Haiti’s capital city of Port-au-Prince at 4:53 p.m. on January 12, 2010. In 2008, Paul Mann and colleagues forecast that due to accumulated strains along a boundary between tectonic plates, a region including Haiti, Jamaica and the Dominican Republic was due for an earthquake on the order of magnitude 7.2.

Japan Earthquake: March 11, 2011
On March 11, 2011, Japan was hit with their largest earthquake in over 100 years. The epicenter of the 9.0 magnitude earthquake (upgraded from 8.9 by the Japan Meteorological Agency on 13th March) occurred at just over 370 km off the coast of Japan, resulting in up to 10 meter high tsunami waves.

• http://adventuresingeology.com/2011/03/11/japans-8-9m-earthquake-march-2011/

You can read about the science behind Japan’s earthquake here:
• http://www.livescience.com/13187-japan-earthquake-tsunami-science-faq.html

A Russian scientist, A. Lyubushin, claims to have predicted the Japan earthquake through analysis of microseismic noise and he produced several papers in 2008, 2009, and 2010 on this topic and summarized his work in an April 2011 presentation found at his website.

Scientists at Japan’s Earthquake Research Institute, University of Tokyo, are using strain meters embedded into the ground to monitor stresses on the fault through measuring the pre-slip (pre-earthquake) activity. Read about it here at The Washington Post website.

Predictions of more aftershocks were reported in the article: Strain from Japan earthquake may lead to more seismic trouble, scientists say (The Washington Post article found here.) “It will take probably a decade before this aftershock sequence is over…”

Earthquake Prediction
There is not yet consensus among the scientific community on earthquake prediction but research in this area continues.

There are several organizations on the web that claim they can predict earthquakes through other methods such as moon phases, human and animal behaviour, micro-earthquakes, thermal temperature changes, ULF or Ultra Low Frequency sounds, or water temperature changes. One organization, named Quake Prediction, claims they can make earthquake forecasts based on “thermal temperature changes caused by kinetic frictional heating of the tectonic plates”. However there is no proven connection between temperature and rock that moves several miles underground, and no consistent theory yet exists that can produce accurate predictions. In spite of this, some organizations continue to post predictions of earthquakes worldwide. One prediction posted for along the California coast resulted in people leaving work and taking their children out of school and in response, the USGS (United States Geological Survey) released a public statement declaring such predictions a hoax.

HEWS (Humanitarian Early Warning Service) provides a Seismic Monitoring Page that shows the latest 50 earthquakes worldwide. You may be surprised about the number of earthquakes we never hear about. This organization predicts many types of natural disasters however, for earthquakes, it only lists them after they have occurred.

"Earthquake prediction is something we haven't really been able to master yet," says Keith Sverdrup, a professor of geophysics at the University of Wisconsin-Madison. [The Science behind Japan's Deadly Earthquake]. "With earthquakes, the best we can say is these are areas where earthquakes are likely to occur and this is our best estimate of the statistical probability of an earthquake of a certain size happening within a certain period of time."