The December 23, 1972 earthquake
M5.2near Kahaluu-Keauhou, Hawaii
A magnitude 5.2 earthquake 21.4 miles deep, centred in Hawaii County. The 73rd strongest in Hawaii’s record since 1900, and the strongest within 50 miles since a magnitude 5.5 on October 23, 1963. 4 aftershocks of magnitude 2.5 or more followed within 30 days.
The earthquake
- Magnitude
- 5.2
- local magnitude (ml)
- Depth
- 21.4 mi
- 34.5 km below the surface
- Local time
- Saturday, December 23, 1972
- 09:04 HST; 19:04 UTC
- In Hawaii’s record
- 73rd
- strongest of 39,637 since 1900
USGS ANSS Comprehensive Earthquake Catalog, event hv19723118 (“0 km NNW of Kahaluu-Keauhou, Hawaii”). 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.
4
Aftershocks in 30 days
4.6
Largest aftershock, Dec 24, 1972
1
On the first day
2
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
- Hawaii CountyHI · inside
Earthquakes around the epicentre
5,231 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
- October 5, 1929M6.5
- March 28, 1915M6.4
- August 21, 1951M6.3
- November 1, 1918M6.2
- June 27, 1962M6.2
- January 2, 1935M5.9
- August 14, 1955M5.7
- September 25, 1929M5.6
- June 28, 1935M5.6
- December 27, 1944M5.6
USGS ANSS Comprehensive Earthquake Catalog. Local time is the time zone of the county nearest the epicentre. Magnitudes are as the catalogue reports them.