Mailing Address:
ODNR Division of Geological Survey 2045 Morse Rd., Bldg. C-1 Columbus, OH 43229-6693 Phone: (614) 265-6576 Fax: (614) 447-1918 E-Mail Location Map
Earthquake Contacts: 24 Hour Earthquake Reporting Hotline: 1-855-QuakeOH 1-855-(782-5364) Media Inquiries Quake Info Center: Michael C. Hansen Phone: (740) 548-5979 Fax: (614) 447-1918 E-mail Web Page
Weak, almost continuous background seismic waves or earth "noise" that can be detected only by seismographs often caused by surf, ocean waves, wind, or human activity.
Bolt, B. A., 1993, Earthquakes: W. H. Freeman and Co., New York, p.310.