Group of BC professors record global earthquakes

While professor Alan Kafka's name may sound familiar to the many students who have taken his Geoscience and Public Policy course, many do not know that he is the chair of the department of geology and geophysics here at Boston College. BC's geology and geophysics department is among the leaders in seismological data gathering at the university level. Just west of the Chestnut Hill campus lies the Weston Observatory in Weston, Mass., which serves as the headquarters for earthquake research and analysis of seismic activity in New England.

"The observatory operates a 12-station regional seismic network across New England as well as educational seismographs in K-12 classrooms in eastern Massachusetts," said Kafka. "These seismographs record earthquakes in New England and across the globe."

The Observatory houses seismic instruments of the World-Wide Standardized Seismic Network (WWSSN) and the New England Seismic Network (NESN). The purpose of the NESN is to monitor seismic activity in the region to gain understanding of the causes of earthquakes in the region and assess the potential for damaging earthquakes in the future. Kafka said, "The purpose of our earthquake research at the observatory is to understand the nature of earthquake activity across the globe with emphasis on earthquakes in the northeastern United States."

In addition to conducting research, the Weston Observatory operates the BC Educational Seismology Project (BC-ESP), with seismographs in place at a dozen K-12 classrooms in eastern Massachusetts. According to Kafka, who directs the BC-ESP, "this project uses seismology as a medium for inviting students into the world of science research by inquiry-based learning through investigation of earthquakes recorded by seismographs in their classrooms," said Kafka.

"Seismology is an interdisciplinary science that requires understanding a wide range of scientific concepts," said Kafka, "and seismology also teaches students how the natural environment impacts our everyday lives."

While the Weston Observatory specializes in earthquakes occurring in the Northeast, its seismographs are capable of recording earthquakes from around the globe. For example, the observatory recorded the magnitude 9.0 earthquake that struck off the west coast of Sumatra, Indonesia on Dec. 26, 2004, which triggered devastating tsunamis throughout Southeast Asia.

More recently, the observatory recorded the magnitude 4.2 earthquake that hit Bar Harbor, Maine, on Oct. 3, as well as the magnitude 6.7 earthquake that occurred on the main island of Hawaii on Oct. 15.

Earthquakes occur when tectonic forces acting on the crust of the earth cause it to break and snap into a new position. When this happens, vibrations called seismic waves are generated and travel through the earth and along its surface.

These vibrations are recorded by seismographs, which are used to determine the magnitude of the earthquake.

"When the magnitude 6.7 earthquake occurred in Hawaii on Oct. 15, the seismic waves that traveled through the Earth were strong enough to be recorded in New England. Earthquakes in Hawaii that are about as large as magnitude 6.0 or greater are strong enough to send seismic signals that are recordable in New England," said Kafka.

The farther away an earthquake hits from the Weston Observatory, the greater the magnitude it must have to register on its seismographs.

"The magnitude 4.2 earthquake that occurred in Maine on Oct. 3 was well recorded by the Weston Observatory seismographs. However, if an earthquake of that size occurred in Hawaii, it would be too small for us to record it," said Kafka.

Additionally, greater distance means it takes longer for the seismic waves to be recorded.

"The seismic waves from the Maine quake took about a minute to reach Weston Observatory, while the waves from the Hawaii quake took about 12 minutes to reach us," said Kafka.

Thanks to the work of Kafka and other seismologists at the Weston Observatory, we are better able to understand the causes of earthquakes and predict where and when they will strike, allowing us increased safety against these violent occurrences.