Earthquakes Now Recorded in Silsby

THE something new that's been added to the third floor corridor of Silsby Hall is a seismograph, a something that the College's Geology Department has long wanted. The man responsible for the operation of the new piece of equipment is Associate Professor of Geology Robert W. Decker (right, above), and he describes the seismograph as a working educational display. "What the pen is writing," Professor Decker notes, "the earth is doing at that very moment."

Shown cutting the ribbon and formally presenting the seismograph to the College, in the photograph above, is William B. Heroy Jr. '37 (left), president of Geotechnical Corporation of Dallas, Texas, the manufacturer of the equipment. Mr. Heroy is a member of the Dartmouth Alumni Council.

The seismograph was given to the College jointly by the Geotechnical Corporation, donor of the recorder; Mr. Heroy, donor of the amplifier; and the National Science Foundation which provided funds for the purchase of the timing system.

Three undergraduate classes, Introductory Geology, Structural Geology, and Geophysics, will use the seismograph records during laboratory sessions. For research it is now an important leg in a triangle between Hanover, Boston, and Maine for precise location of New England earthquakes whose origins are mysterious - but may be still due to rebounds from the Ice Age.

The seismograph has a round-the-world range, depending upon the size of the earthquake. Professor Decker reports the seismograph locates about one moderate or larger quake every three days. In favorable circumstances the geologists can tell the distance to the quake. Triangulation through the three New England stations determines location. The Dartmouth seismograph can pick up underground nuclear blasts.