Introduction
Haiti's disaster
Turkey's tragedy
Long time shaking
Plate tectonics
Finding faults
Proving the theory
Perilous predictions
Safe buildings
1999-2004 Activity
Introduction
Jan. 2012. The past seven years have been very active around the world for earthquakes.
The earthquake record for 2011 is clearly dominated by the great Tohoku magnitude 9 quake on March 11 that caused the deaths of over 20,000 people in Japan and caused the nuclear power plant disaster that still has portions of the NE coast of Japan uninhabitable. There were no other quakes in 2011 with magnitudes greater than 8 - the largest earthquake in the continental US occurred somewhat unexpectedly in central Virginia - a magnitude 5.8 event five months ago on August 23rd that was newsworth both for its location and the fact that people felt it as far away as Boston.Click here to see a variety of summaries of quakes during 2011.
Certainly the most newsworthy earthquake of 2010 was the magnitude 7.0 Jan. 12 quake that caused the deaths of over 230,000 Haitians - a disaster that will continue to affect that poor country for years to come. In addition to this catastrophe there were nearly two dozen quakes in 2010 that released more energy than the Haiti quake. The most energetic was a magnitude 8.8 quake offshore of Chile on Feb. 27. This has been the strongest quake since the Boxing day (Dec. 26) 2004 quake that caused the devastating tsunamis in the Indian Ocean. Click here if you would like to review the important seismic activity during 2010. The lack of a direct correlation between magnitude and fatalities is one of the lessons taught by this module.
2009 was one of the least deadly years in recent history despite the fact that there were 17 quakes with magnitudes greater than 7.0 including an 8.1 in the SW Pacific. The latter, which caused a tsunami that killed nearly 200 people, occurred one day before the deadliest quake of the year - a magnitude 7.6 quake in Indonesia that caused over 1700 fatalities. By the end of this module I hope that you will understand why the timing of these two quakes was purely coincidental and neither a conspiracy by Mother Nature nor Lex Luthor (my ONLY movie link).
In 2008 the May 12th earthquake in the Sichuan Province of China was the largest and deadliest of the year. This magnitude 7.9 quake killed nearly 90,000 people, injured over 375,000 and displaced millions from their homes. Here is a link directly to the U.S. Geological Survey's summary of this disaster and here is a link to the USGS summary page of all the significant earthquakes of 2008. In this course you will learn that this quake was caused by the continued northward insertion of India under Tibet and the accomodation of this by pieces of China trying to slide out of the way to the north and east.
For 2007 the largest quake (Mag 8.4) occurred in Sumatra however the deadliest quake was the Magnitude 8.0 quake near the coast of central Peru that caused over 500 deaths. The U.S.G.S. keeps tabs on these things and here is a link to their summary of 2007.
As summarized here the largest quake (Mag 8.3) in 2006 took place in the NW Pacific on November 15 beneath the Kuril Islands. Follow this link to a brief summary of the quake and discussion of the ensuing tsunamis (or lack thereof). [Interestingly, on January 13, 2007 another Mag. 8.1 quake took place at almost the same spot and again caused no damage and no tsunamis.]
The deadliest quake in 2006 occurred on May 26 beneath Java and although its Magnitude was only 6.3, it killed nearly 6000, injured 38,000+ and displaced more than a half million people while destroying 127,000+ homes. A third notable quake (Mag 6.7) took place on October 15 beneath the Big Island of Hawaii. I hope that by the end of this Earthquake module you will appreciate how odd it is that this relatively strong quake occurred in the middle of the Pacific tectonic plate.
The largest quake in 2005 was a magnitude 8.7 quake off northern Sumatra in March - the quake occurred just south of the tsunami-causing quake of Dec. 26, 2004. While the cleanup of civilization's debris continues in this region, portions of the coast lines were changed dramatically - here is a picture from the National Geographic showing the result of uplifting a coral reef about 3-4 meters.
The deadliest quake of 2005 was Oct 8 in northern Pakistan
with more than 86,000 fatalities. Here
is a link to a summary page about this quake. You should probably
come back to this page and follow these links after working through this
module. The best summary source for information is provided by the U.S.
Geological Survey - here is the
link to the 2005 summary.
Jan. 2005. Sunday Dec. 26, 2004
brought with it the 4th largest earthquake in the past century but tragically
we don't really know how much damage the quake itself did as the real
impact of the energy release was in the deadliest tsunami in recorded
history. The magnitude 9.0 quake off the coast of Sumatra and its associated
tsunami devastated coastal areas of Indonesia, Thailand, Malaysia, Myanmar,
Bangledesh, India, Sri Lanka, the NE coast of Africa and various islands
in the Indian ocean. Click
this link for a page with some details of this disaster and links
to other sources.
Three days prior to the Sumatran quake the then largest quake of the year (temporary honor indeed), a magnitude 8.1 temblor, occurred off the southern coast of New Zealand and did no damage at all, even to the penguin communities on Macquarie Island near the epicenter. Follow this link to see why this quake was so innocuous.
Click here to see the U.S. Geological Survey's compilation of the busy year that was 2004 in the earth quake area.
Is this level of earthquake activity normal? How are these quakes related to each other? What causes earthquakes anyways and why can't we predict them?
These questions and more will be addressed in this module. The devastating earthquake that occurred in August of 1999 in Turkey provides the backdrop for our discussion of Why a quake, Where a quake, Everywhere? an earthquake.
In addition to investigating why earthquakes occur where they do, part of the focus of this module is on the range of problems that result from the earthquake beyond the shaking. Sometimes landslides may be one result. Sometimes it is fires. Sometimes 'tidal' waves.
Before we dive into this material here is a suggestion for those of you with good internet connection speeds and a decent size monitor. Open (and leave open) a 2nd browser window with this link to Seismic Monitor page maintained by IRIS, a university-research consortium dedicated to understanding the Earth using seismic information. The graphic on this page will update every few minutes and shows the recent earthquakes around the world.
Let's get ready to rumble! - with a choice. Click Here for a summary of the years 1999-2004 or click the More button below to begin the systematic treatment of earthquakes in general. Make sure that eventually you follow both branches of this story.
