Historic Earthquakes

Near the Copper River delta, Alaska
1899 Sep 23 11:04 and 12:50 UTC
Magnitudes 6.9 and 7.0

Eight shocks were noted in the Coast and Geodetic Survey camp, one of which was strong enough to awaken everyone in the camp. A plumb bob vibrated through 25 centimeters from northwest to southeast; the vibrations were distinct and slow.

Abridged from Seismicity of the United States, 1568-1989 (Revised), by Carl W. Stover and Jerry L. Coffman, U.S. Geological Survey Professional Paper 1527, United States Government Printing Office, Washington: 1993.