A team of geophysicists led by Rensselaer Polytechnic Institute Professor Steven Roecker is in Chile to study the scope and strength of aftershocks that continue to rattle the area following the massive Feb. 27 8.8-magnitude earthquake. The 10-member team, which was assembled quickly from universities around the United States, will be putting in place more than 50 broadband seismometers throughout the impacted area in Chile.

“This earthquake is the fifth largest megathrust earthquake to be recorded,” said Roecker, professor of earth and environmental sciences at Rensselaer. “As such, it presents scientists with an unprecedented opportunity to study the aftershocks and related geologic phenomena.”

The research is funded by a Rapid Response Research (RAPID) grant from the National Science Foundation (NSF).

The aftershocks, which range from minor vibrations to substantial earthquakes such as the 6.9-magnitude aftershock that occurred on March 11, could go on for more than a year following an earthquake of this magnitude, according to Roecker. The array of seismometers to be installed over the next several weeks will record all seismic activity along a 500-kilometer zone stretching south of the city of Santiago.

“We are looking to capture as much seismic activity as we can,” he said. “What geophysicists know is that the Earth does substantial readjusting right after an earthquake, so quick monitoring in the aftermath is essential. Seeing these geologic modifications in real time gives us the chance to study the normally slow physical changes that occur under the earth extremely fast. We can acquire a wealth of knowledge on some of the most basic, million-year processes of the Earth in a few months.”

The scientists can also start to pull together important clues about what exactly occurred under the earth in Chile on Feb. 27, Roecker said.

The overall goal of the project is to produce an open source of data on the earthquake for a large range of existing scientific projects. Some potential uses for the important data include studies on the potential for other earthquakes in the region, the development of seismic images of the fault zone and how that is changing over time, the identification of stress patterns in the surrounding portions of the fault zone, and comparisons between other active geologic zones in the world.

“A large earthquake was not unexpected in Chile. But, what we already know is that the exact location of this earthquake was a bit unexpected,” Roecker said. “The northern portion of this fault was expected to slip first. The fact that the southern portion was the part to rupture leads to many questions about the additional strain that has accumulated at the already tenuous edges to the north.” The data being provided by the research excursion could provide important clues about the stability at the edges of seismic zone.

Roecker and members of the team expect to return to Chile several times over the next six months to continue their studies and equipment setup. He hopes that Rensselaer students will have the opportunity to travel with him on these future trips.

Roecker, who is also an active teacher at Rensselaer, focuses his research on the gathering and analysis of geophysical data. He utilizes information from seismometers as well as Global Position Systems (GPS) and studies of gravity to learn how the earth moves over time. His research takes him frequently to Tibet and Central Asia. He began a partnership with scientists in Chile more than 20 years ago and most recently received a Fulbright scholarship to continue his study of the subsurface geology in the country.

Contact: Gabrielle DeMarco
Phone: (518) 276-6542
E-mail: demarg@rpi.edu