Satellite map showing 24 proposed locations for seismic monitoring. Kotowski visited them all. Illustration: © 2012 Google, © 2012 TerraMetrics, © 2012 Cnes/Spot Image. Click image to enlarge.

Geological sciences major Alissa Kotowski ’14 spent last summer scouting the northeastern states for locations that are, in the words of her professor John Ebel, “as far into the middle of nowhere as you can get.” Her work was part of a 10-year National Science Foundation–funded study to take the continent’s pulse by systematically planting motion-sensing equipment (seismometers) in a dense grid across the United States and southern Canada. Ebel, who is director of Boston College’s geophysical laboratory at Weston Observatory, oversaw Kotowski’s participation in the project, called EarthScope.

The monitoring began on the west coast in 2004 with 400 sensors positioned 42 miles apart. The seismometers spent 18–24 months buried six feet underground—transmitting seismic recordings to a central data bank at the University of California, San Diego—then were unearthed and shifted further east to new sites, where the process was repeated. The goal of the project, which in the end will have monitored some 2,000 locations nationwide, is to develop the most detailed picture of North American geologic activity to date.

The seismometers are each about the size of a basketball and weigh 20 pounds. They register vibrations in three orientations (up-down, north-south, east-west). At burial, each unit is housed inside a protective plastic cylinder that Kotowski has described to landowners as “about the size of a large refrigerator.” Above ground, a pole supports a solar cell for power and a cellular, broadband, or satellite link for transmitting readings.

Kotowski and a coworker spent 10 weeks identifying two dozen quiet spots in the noisy northeast, from Nantucket, where pounding surf can produce distracting vibrations, to the northern Adirondacks, where the dense forests make it hard to get enough light to power a solar panel and the shifting roots of trees swaying in the wind are apt to be mistaken for seismic activity. Kotowski used a map created by EarthScope (above), which defined, with circles, the locales where she should search (different colors denote more or less promising areas within each). EarthScope stipulated the distance from roads (1–3 km, depending on traffic volume), parking lots (200 m), irrigation pumps (1–3 km), and windy hilltops. In one two-week period Kotowski covered more than 2,000 miles in rented vehicles, stopping at farm stands, knocking on doors, and coming away with three installation agreements. Most of the 24 sites she secured are in farm fields. These are not entirely free of extraneous vibrations, says Kotowski, but “it’s pretty easy to tell what’s a tractor and what’s an earthquake.”

Read more by Thomas Cooper