I knew earthquakes could make an island 'sink' or slide into the ocean. I have never heard of one rise up. ??? Is it only along this plate that it happens? Residents of Ranongga island in the South Pacific Ocean sit on a massive coral reef that was exposed by the magnitude 8.1 earthquake that struck in the Solomon Islands in April 2007, sparking a deadly tsunami. The quake lifted Ranongga ten feet out of the sea, widening beaches by up to 230 feet, according to news reports. The uplift has left some of the island's pristine coral reefs fatally exposed. "These are not unusual occurrences for an earthquake of this magnitude," said Rick MacPherson of the Coral Reef Alliance in San Francisco, California. "During the Asian tsunami two years ago, Banda Aceh [in Indonesia], stretching down almost the extent of the peninsula, experienced similar uplift." In some places the beaches in the Solomons now resemble a barren moonscape with once vibrant corals bleaching under the sun. On one beach the quake even revealed a sunken vessel that locals believe is a Japanese patrol boat from World War II. Please Register or Log in to view the hidden image!
It's a case of elastic rebound. The subducting plate tends to bend the upper plate down with it, building strain. The strain builds until the faultline slips, (earthquake) and the upper plate rebounds upwards. This motion is what caused the tsunami in 2004 as the rebounding plate pushed against the ocean.
Are the most frequent earth quakes now reported in the southern hemisphere? Do more earth quakes happen in the southern hemisphere as opposed to earth quakes in the northern hemisphere. DwayneD.L.Rabon
no, there are roughly the same number in the North and South hemispheres - they are focused along plate boundaries. In the southern hemisphere, there are a lot of people living in SE asia, along the major tectonic plate boundary there; thus we hear about it more than those earthquakes occurring in the remote islands of Alaska. http://earthquake.usgs.gov/eqcenter/recenteqsww/
There are many kinds or causes of quakes. Knols and Mountains, especialy mountains are caused by plate shifts, which is characterized by quakes also.
