Monday, March 14, 2011
In our EarthView programs we always mention plate tectonics, because our perspective from inside the planet helps us to understand the relationships among the constantly shifting positions of plates relative to each other, and the growth of oceanic plates. We often point out the Pacific Ring of Fire -- the series of convergent and transform boundaries that surround the Pacific Ocean and that are responsible for many of the world's earthquakes, and of the subduction zones that are associated with convergent boundaries and are associated both with earthquakes and with the formation of some volcanoes. (Volcanoes can also be formed from hot spots.)
The Pacific map below shows the locations of major fault systems, plates, and volcanic activity surrounding the ocean. The image is part of an article on subduction zones found on the Geology and Landforms of Japan web site.
When talking about subduction zones and the formation of volcanoes, geographers often wave their hands to illustrate the relative positions of dense oceanic plates, less-dense continental plates, and volcanic activity. The illustration below -- from the same article on subduction -- provides a much clearer image. See the article for more detail.
Compared to other countries that have endured earthquakes and/or tsunamis in recent years -- such as Indonesia and Haiti -- Japan is much wealthier and has been considered much better prepared to cope with both kinds of disasters. Located at the convergence of three major plates -- Pacific, Eurasian, and Philippine -- Japan has been forced to consider tectonic activity in all of its building and planning.
Tragically, the March 11 earthquake was the strongest ever recorded in Japan, so the damage has overwhelmed many of its systems. The Boston Globe has posted very powerful images of the destructive power of this combined disaster in two photo essays - Massive Earthquake Hits Japan and Earthquake Aftermath. The Globe also posted a series of informative, interactive graphics under the title Disaster in Northeast Japan. This page includes three tabs: a map of Japan's nuclear power plants relative to the disaster, an animation that illustrates the spread of the tsunami wave through the Pacific (a static version is shown below), and an animation that illustrates how tsunami waves travel, and why they might not even be detected by the boats they pass under!.
Bridgewater State University has long-standing relationships in Japan, with exchanges dating back more than a century! Many short-term and long-term BSU students are Japanese citizens, and many BSU students travel to Japan for study tours or semester-long exchanges. For this reason, our campus has been very concerned about the tragedy facing the country, and BSU's Asian Studies Program has taken a lead in sharing information about news from the disaster and ways people can help.