The June 10, 1912 earthquake
M6.8Event 48 Novarupta-Mount Katmai area, Alaska Peninsula
A magnitude 6.8 earthquake 3.1 miles deep, centred in Lake and Peninsula Borough. The 118th strongest in Alaska’s record since 1900, and the strongest within 50 miles since a magnitude 6.8 on June 7, 1912. 2 aftershocks of magnitude 2.5 or more followed within 30 days.
The earthquake
- Magnitude
- 6.8
- moment magnitude (mw)
- Depth
- 3.1 mi
- 5.0 km below the surface
- Local time
- Monday, June 10, 1912
- 06:06 AST; 16:06 UTC
- In Alaska’s record
- 118th
- strongest of 124,625 since 1900
USGS ANSS Comprehensive Earthquake Catalog, event official19120610160606500 (“Event 48 Novarupta-Mount Katmai area, Alaska Peninsula”). 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.
2
Aftershocks in 30 days
6.2
Largest aftershock, Jun 17, 1912
0
On the first day
47
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.
- Before the modern seismic networks of the 1970s many small aftershocks went unrecorded, so early sequences read short.
Counties and cities within 50 miles
Distance from the epicentre to each county boundary (zero when inside) and to each city centre.
Counties
- Lake and Peninsula BoroughAK · inside
- Kodiak Island BoroughAK · 3.2 mi
- Kenai Peninsula BoroughAK · 33.0 mi
- Bristol Bay BoroughAK · 47.2 mi
Earthquakes around the epicentre
634 earthquakes of magnitude 3 or more within 50 miles of this epicentre since 1973.
Earlier earthquakes of magnitude 5 or more within 50 miles, strongest first
- June 7, 1912M7.0
- June 7, 1912M6.8
- June 8, 1912M6.6
- June 7, 1912M6.5
- June 6, 1912M6.3
- June 7, 1912M6.3
- June 7, 1912M6.3
- June 8, 1912M6.2
- June 7, 1912M6.1
- June 7, 1912M6.0
USGS ANSS Comprehensive Earthquake Catalog. Local time is the time zone of the county nearest the epicentre. Magnitudes are as the catalogue reports them.