New recording‐vault of the Harvard Seismograph‐Station

Abstract

The Harvard seismograph‐station, after 25 years of operation in the Geological Museum, Cambridge, is now housed in a new vault at Oak Ridge, Massachusetts, near Harvard and about 25 miles northwest of Cambridge. The coordinates of the station, determined astronomically, are 42° 30′ 26″±1″ north latitude and 71° 33′ 45″±15″ west longitude. The new vault has been constructed as a unit of the research program directed by the Harvard Committee for Geophysical Research, and financed jointly by the Rockefeller Foundation and by friends of the Division of Geological Sciences at Harvard. The opening for the main room was excavated from solid rock, a Paleozoic micaceous schist, to a depth of over 15 feet. The room is 22 feet square inside. Two corners are occupied by small piers, and the main pier is an octagonal strip five feet wide. Its open center makes all parts readily accessible. The piers and floor were poured as a unit with the underlying rock. An eight‐foot covering of dirt renders the temperature in the vault practically constant; thorough waterproofing has prevented any infiltration of water; and calcium‐chloride driers are proving entirely satisfactory for the control of humidity. A small work‐shop adjoins the vault. A special dark‐room is located in a separate building. A standard B. Howard pendulum‐clock is used for timing. It is checked with NAA time‐signals by means of a short‐wave radio receiver. The clock is mounted in the main vault under optimum conditions. In the first three weeks of service its rate was reduced to one second per week, and it is expected this will be further improved.

Efforts to Recover and Digitize Analog Seismograms from Harvard-Adam Dziewo ski Observatory

“…Original plan of the HRV seismograph station from 1933 found in the archives at the Albuquerque Seismological Laboratory, U.S. Geological Survey (USGS) by C. R. Hutt. This plan has also been published in Leet (1934) as volume 24, plate 5. The above-ground brick building that exists today was added later to provide work space at the station.…”

“…There are two primary publications that give information about instruments used at the station. The first, and the most important, is a Bulletin of the Seismological Society of America report by Leet on the "New recording vault of the Harvard seismograph station" (accepted in August 1933 for publication) that describes the station and instruments that were or were being planned to be deployed (Leet, 1934). The second source is a pamphlet, Geophysics at Harvard, which contains photographs and a brief description of the facility.…”

“…The Harvard-Adam Dziewoń ski observatory is one of the oldest seismic stations academically established in the United States, and it is owned and maintained by Harvard University (Leet, 1934). It is currently one of the Global Seismic Network stations operated by the U.S. Geological Survey (USGS)'s Albuquerque Seismological Laboratory (network code IU) and is also used as a testing facility for new instruments by Quanterra, Inc.…”

“…B. Woodworth, who began seismic instrumentation in 1908 (Leet, 1934). Initially, two Bosch-Omori 100 kg horizontal pendulum seismographs were installed in the basement of the Harvard Museum of Natural History building in Cambridge, Massachusetts, and the two instruments operated until 1928.…”

“…1), one that is used today, was constructed at the Oak Ridge Observatory, also known as Harvard Astronomical Observatory, at Harvard, Massachusetts (note that this is about 40 km northwest of Cambridge, Massachusetts, where Harvard University is located). Instruments began recording ground motion at the new seismic station on 30 March 1933 (Leet, 1934). Continuous monitoring of ground motion was carried out for the next 20 years, until the end of July 1953.…”