We walk on solid ground, but few of us know what lurks below the earth's surface.
One man, Dr. John Paul Puchakayala, a post-doctoral student at the Center for Earthquake Research and Information (CERI) at The University of Memphis, is intimately acquainted with the inner workings of this planet. Feb. 26, he returned home from a 40-day excursion through an area east of mainland India, known as the Andaman and Nicobar Islands, where he set up a Global Positioning System.
"I was setting up a few temporary and one permanent or continuous GPS sites for measuring and monitoring the crustal deformation of the region," he said. The continuous site is already giving CERI researchers a run for their money with the recent Indonesian quake.
Monday's magnitude 8.7 earthquake in Northern Sumatra came as a surprise to CERI scientists, as Puchakayala said prior to the event there is usually no more damage following such a large quake as the December one. However he said that Monday's events are probably tied to aftershocks of the Dec. 26 disaster.
Residents felt the quake in the Andaman and Nicobar Islands Monday, but Puchakayala said he spoke to contacts in the islands who reported very little impact, although they were warned to flee to higher locations in case of a repeat tsunami catastrophe.
Researchers at CERI are currently running data on the recent quake from the GPS site Puchakayala set up in January and February.
This job is not new to Puchakayala. From 1995 to 1999, he carried out GPS measurements throughout the Andaman Islands while working for the Center for Mathematical Modeling and Computer Simulation in Bangalore, India. For his bachelors, masters and doctoral degrees in science, he attended Osmania University in Hyderabad, India.
The region is located at the northern tip of the Sumatra earthquake zone, where catastrophe struck throughout southeast Asia Dec. 26, paralyzing many countries, wiping out hundreds of thousands of homes and stealing the lives of more than 280,000 people.
Puchakayala's recent GPS installation near the earthquake's origin will help researchers at CERI monitor any further seismic activity. With the GPS information, scientists will be able to construct more realistic and up-to-date earth models useful in seismic research.
Near the GPS installation site, destruction dots the landscape of what were once popular tourist destinations.
"When I arrived on Jan. 9, I was shocked to see how the tsunami slapped the islands with very long-lasting destruction," Puchakayala said. "Many lost their homes and agricultural land. Tourism came to a complete halt and many daily-waged workers left for mainland India."
The actual earthquake did not cause most of the damage, but since the earthquake occurred in the Indian Ocean, the sudden movement of ocean plates cooked up tsunamis that were recipes for disaster.
The disaster caused many complications for Puchakayala's work.
"Travel to various islands has become very difficult, and local government is strictly monitoring people going to some affected islands," he said.
But as he is from India, Puchakayala is familiar with the area, a quality that made him a good candidate for the CERI project.
During the CERI assignment, he noticed major changes in the landscape and daily lives of the affected people. Those whose homes were situated in low-lying areas watched as the seawater consumed their land due to subsidence. The subsidence caused the area to sink knee deep or more in water.
"There are major landscape changes, especially in the Nicobar Islands like Katchal and Great Nicobar," he said. "Large areas of land were eaten off by the tsunami and subsidence, topography and bathymetry of the region need to be surveyed all over again."
The CERI mission will gather data that will be used for post-seismic adjustment of the plate boundaries.
"This will lead to a better characterization of viscous parameters of the plate boundary and the development of future seismicity," Puchakayala said.
The GPS system will measure the position of the antenna for 24 hours a day, seven days a week. The continuous GPS site was built with a pillar that descends into the earth about eight feet with a 10 feet square base on the surface to ensure stability. National Science Foundation, CERI and The University of Memphis, and the University of Colorado at Boulder funded the project.
Dr. Bob Smalley, a researcher at CERI who collaborated with Puchakayala about the GPS project, described an earthquake's actions and how the GPS is of use.
"Before the ocean plates make the earthquake, the rocks deform and build up energy just like if you stretch a spring," he said. "If you stretch a spring, get to the point where you can't pull it anymore and let go, it jumps back. The earth does the same thing.
"The GPS station will measure the position of the antenna, so we can see the ways things are moving in the Andaman and Nicobar Islands region."
While the northern Sumatra earthquake happened last December, the CERI researchers submitted their proposal to set up GPS sites to the National Foundation of Science in June 2004. The NSF is responsible for large portions of earthquake research funding. Smalley said they picked this region because "it's an area where, for some reason, nobody had put any equipment yet to do a study."
If there is already a project set up in a particular region, then another research team may not come in and set up the same work. "You can write a proposal to do other things, but you can't write a proposal to do the same thing," Smalley said. "Most of the plate boundaries that were accessible already had projects put on them, and this area was a little hole."
But that little hole caused a whole lot of damage in December, and now Smalley said the area is really worth focusing on to see how the earth will respond to the earthquake, especially in the recent wake of Monday's quake. The earth's response should last for many years because of the magnitude of the Dec. 26 quake.
Puchakayala said CERI would focus on setting up more GPS sites in the islands while working with local scientific institutions in India. "We hope to resolve the active vertical and horizontal deformation the region is going through," he said. Until they do, trying to walk on solid ground in the southeastern Asian regions may have people wondering more about what's under the earth than what's on top.
