Meltzer probes how the earth works

	Anne Meltzer, front left, works with her research team on a previous expedition to Ecuador.

Anne Meltzer, professor of earth and environmental sciences, travels the globe to observe earthquakes and to gauge the role they play in shaping the earth's interior and its crust.
In October, two months after her appointment as the Herbert J. and Ann L. Siegel Dean of the College of Arts and Sciences, Meltzer flew to Tibet to retrieve earthquake-monitoring equipment that had been placed there a year earlier.
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Tibet is an ideal natural laboratory for a seismologist, Meltzer says. It sits behind the Himalayas, the world's highest mountain range, and one of the most dynamic regions of the earth's surface, where the advancing Indian subcontinent descends beneath the Asian continental mass. The collision of the two tectonic plates thrusts rock up from under the earth's surface and pushes the Himalayas ever higher.
Meltzer and Peter Zeitler, professor of earth and environmental sciences, lead an international research team that is studying the vicinity of Namche Barwa, highest peak in the eastern Himalayas. This is the second five-year international research project the two professors have led in the Himalayas, the first being in Pakistan. Both were funded by the National Science Foundation, and both have involved Lehigh students.
Meltzer and Zeitler are researching whether and how much the forces of surface erosion -- wind, rain, rivers -- influence the tectonic forces below that give rise to earthquakes, volcanoes, mountain-building, and more.
We want to see how the earth works, Meltzer says. Tibet is a great place to do this, because the Himalayas are very active; the mountains are forming now. We want to see the physical properties of the earth beneath Tibet and locate the active faults and see how they form as tectonic plates collide.
To see beneath Tibet and into the earth, Meltzer and her group placed 70 seismometers across southeastern Tibet. From initial planning to final installation, the process took three years, thanks to language differences, Tibet's restricted status, and its unpredictable weather and roads. The seismic stations remained in the ground for 15 months taking data.
Doing research in Tibet involves a high degree of uncertainty, Meltzer says. You have to plan with infinite detail and infinite flexibility. Much of Tibet is restricted; you need permission to enter the country and you need Chinese colleagues with you for collaboration.
The seismic instruments record the motions of the ground during earthquakes, both local events and those happening around the world. Using sensors to analyze the vibrations occurring inside the earth during an earthquake, says Meltzer, geologists can map out the earth's core, mantle, and crust and infer their properties. The high-tech probing is analogous to the way ultrasound scopes the interior of the body, the difference being that an earthquake sends out elastic energy while ultrasound uses acoustic waves.
Meltzer takes particular pride in the accomplishments of her students, who often accompany her on her travels. Several made presentations in December at a conference of the American Geophysics Union in San Francisco.
I think it really expands students' horizons when they travel at such a young age to other countries, she says. It can be intimidating to deal with new situations, but at the same time they gain a sense of confidence and what they can do. It helps them learn how to solve problems and interact with new people.
--Kurt Pfitzer
Lehigh Alumni Bulletin
Winter 2005

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