Links Between Erosion, Runoff Variability And Seismicity In The Taiwan Orogen
Results from one of the most comprehensive studies of erosion of the earth's surface have revealed the detailed spatial pattern of erosion in the Taiwan mountain belt. The findings, recently reported in Nature, provide evidence that mountain erosion can be directly related to large earthquakes and storms. Taiwan is one of the most rapidly eroding mountain belts on earth, with average erosion rates of 3-6 mm per year and extreme rates of 60 mm per year in some areas of weak rock that have recently experienced large earthquakes and storms.
An international team of scientists from Cambridge University's Department of Earth Sciences, the National Taiwan University, the University of Washington, and Lamont-Doherty Earth Observatory of Columbia University in the USA, are attempting to understand erosion of tectonically active mountain belts. This study will help explain the links between tectonics, climate, and erosion, and will provide vital information to combat natural hazards such as landslides, floods, and earthquakes.
The new results show that on time-scales of millions of years, erosion rates in the Taiwan mountains balance the upward movement of the earth's crust. Between 1970 and 1998, erosion rates were highest in areas where large earthquakes and storms had occurred. These results pave the way for future investigations into the detailed impact of individual earthquakes and storms like the 1999 Mw 7.6 Chi-Chi earthquake and the recent typhoons Bilis and Toraji, which altogether claimed 3,800 lives and cost 15 billion US dollars.
To view a slide show illustrating the erosion of the Taiwanese landscape, click here. These photographs, including the one at right, were taken by Colin P. Stark during two field seasons in Taiwan in September 2002 and January 2003, the latter around the time of a major GSA Penrose conference on tectonics, climate and erosion held in Taroko National Park.
To read the paper in Nature, visit: http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v426/n6967/full/nature02150_fs.html
For an article on the general science of erosion, covering topics such as the role of tectonics versus the role of climate in erosion, please visit http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v426/n6967/full/426612a_fs.html
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