←Back

Recent major earthquakes A study of recent major earthquakes reveals that they each have different distinguishing characteristics. On the globe at left, look at "Major earthquakes 2003-2006." The results show the locations of five quakes that caused major damage between the end of 2003 and May 2006. Southern Iran Earthquake Date: December 26, 2003 Magnitude: 6.3 Iran is a particularly earthquake-prone country where three different plates (the Eurasian, Arabian, and Indo-Australian plates) collide. It is thought that this quake was the result of movement of these plates producing strain in an inland active fault. Because it was an extremely shallow earthquake whose epicenter was just 4 km below the Earth's surface, the damage was severe. There was extensive damage in and around the city of Bam, which is directly above the epicenter, with as many as 40,000 people losing their lives. Niigata-Chuetsu Earthquake Date: October 23, 2004 Magnitude: 6.8 Like Iran, Japan is located in an area where several plates (the Pacific, Eurasian, and Filipino plates) collide, and is therefore very prove to earthquakes. Moreover, tremors occur not only on the Pacific Ocean floor along the boundaries of these plates, but also directly beneath the islands that make up the Japanese archipelago. These latter types of earthquake are known as shallow inland earthquakes. Examples include the Great Hanshin-Awaji Earthquake (January 1995) and the 2004 Niigata-Chuetsu Earthquake. They occur when pressure from one or more plates causes the islands of Japan themselves to twist and bend. Earthquakes that occur inland are less powerful than earthquakes that occur in submarine trenches, but because they often happen directly beneath areas where people are living, they tend to cause considerable damage. Sumatra Earthquake Date: December 26, 2004 Magnitude: 9.0 In the area off the coast of the island of Sumatra where this earthquake was centered, the Indo-Australian plate is sinking under the Eurasian plate (on which Sumatra is located) at a speed of 7-8 cm a year. The collapse of the earth's crust that signaled the start of this quake is thought to have occurred on the ocean floor tens of kilometers below the surface near the island of Simeulue, which is situated north of the island of Sumatra, and ultimately extended over an area some 1000 km in length. The resultant tsunami affected a wide area resulting in the deaths of tens of thousands of people in coastal regions. This was the first magnitude 9 quake to occur anywhere in the world in the last 40 years, and the tsunami it triggered is said to have circled the globe five times. Northern Pakistan Earthquake Date: October 8, 2005 Magnitude: 7.6 The area hit by the Northern Pakistan earthquake lies at the foot of the Himalayas. The Himalayan Mountains were originally formed when the Indian continent collided with Asia, the topography in the area the result of the earth's crust being pushed up sharply in the aftermath of this collision. Earthquakes occur from time to time in areas like this where one continental plate collides with another. They occur less frequently than submarine trench quakes that strike in areas where one plate moves under another, but when they do occur they tend to result in considerable damage due to the fact that their epicenters are close to the surface of the land. Java Earthquake Date: May 27, 2006 Magnitude: 6.3 This earthquake caused major damage due to the fact that the Earth's crust buckled in two stages. It is possible that magma activity at the Mount Merapi volcano, which is north of the quake's epicenter and was showing signs of activity at the time, caused the quake, although this has not been verified. Some researchers believe it was not related to any volcanic activity, but probably caused by a collision of the Australian and Sunda plates.

←Back