This is a long-period horizontal seismometer, likely built for the World Wide Standard Seismological Network (WWSSN) in the early 1960s. The WWSSN was designed to detect underground nuclear tests. Further information about this type of instrument can be found at the Smithsonian's National Museum of American History (http://americanhistory.si.edu/collections/search/object/nmah_1445876 ).

This is a long-period horizontal seismometer, likely built for the World Wide Standard Seismological Network (WWSSN) in the early 1960s. The WWSSN was designed to detect underground nuclear tests. Further information about this type of instrument can be found at the Smithsonian's National Museum of American History (http://americanhistory.si.edu/collections/search/object/nmah_1445876 ).

Date: Feb 11th, 2015
Volcano(es):
Photographer: Cameron, C. E.
URL: avo.alaska.edu/image/view/77051
Image courtesy of the AVO/ADGGS.
Please cite the photographer and the Alaska Volcano Observatory / Alaska Division of Geological & Geophysical Surveys when using this image.
Full Resolution.