The October 7, 1983 earthquake
M5.1Blue Mountain Lake, New York
A magnitude 5.1 earthquake 7.8 miles deep, centred in Essex County. The 3rd strongest in New York’s record since 1900, and the strongest within 50 miles in the catalogue, which runs from 1900. 3 aftershocks of magnitude 2.5 or more followed within 30 days.
The earthquake
- Magnitude
- 5.1
- body-wave magnitude (mb)
- Depth
- 7.8 mi
- 12.5 km below the surface
- Local time
- Friday, October 7, 1983
- 06:18 EDT; 10:18 UTC
- In New York’s record
- 3rd
- strongest of 187 since 1900
USGS ANSS Comprehensive Earthquake Catalog, event usp0001yuv (“The 1983 Blue Mountain Lake, New York Earthquake”). The USGS event page carries the ShakeMap, felt reports and the official summary.
Aftershocks
Earthquakes of magnitude 2.5 or more within 20 miles of the epicentre in the 30 days after.
3
Aftershocks in 30 days
3.5
Largest aftershock, Oct 7, 1983
2
On the first day
0
In the 7 days before
- The search radius is the surface rupture length expected for an earthquake of this magnitude (Wells and Coppersmith, 1994), at least 20 and at most 600 miles, so a great earthquake's sequence is counted along its whole fault.
Counties and cities within 50 miles
Distance from the epicentre to each county boundary (zero when inside) and to each city centre.
Counties
- Essex CountyNY · inside
- Hamilton CountyNY · 2.2 mi
- Warren CountyNY · 14.6 mi
- Franklin CountyNY · 16.0 mi
- St. Lawrence CountyNY · 17.7 mi
- Herkimer CountyNY · 31.0 mi
- Clinton CountyNY · 38.1 mi
- Saratoga CountyNY · 39.4 mi
- Washington CountyNY · 40.8 mi
- Addison CountyVT · 41.4 mi
- Rutland CountyVT · 46.2 mi
- Lewis CountyNY · 46.5 mi
- Fulton CountyNY · 47.6 mi
- Oneida CountyNY · 48.0 mi
Earthquakes around the epicentre
17 earthquakes of magnitude 3 or more within 50 miles of this epicentre since 1973.
No earlier earthquake of magnitude 5 or more within 50 miles in the catalogue since 1900.
USGS ANSS Comprehensive Earthquake Catalog. Local time is the time zone of the county nearest the epicentre. Magnitudes are as the catalogue reports them.