The September 25, 1929 earthquake
M5.6near Kalaoa, Hawaii
A magnitude 5.6 earthquake, centred in Hawaii County. The 35th strongest in Hawaii’s record since 1900, and the strongest within 50 miles since a magnitude 6.4 on March 28, 1915. 1 aftershock of magnitude 2.5 or more followed within 30 days.
The earthquake
- Magnitude
- 5.6
- surface-wave magnitude (ms)
- Depth
- —
- Not recorded
- Local time
- Wednesday, September 25, 1929
- 18:20 HST; 04:50 UTC on Sep 26, 1929
- In Hawaii’s record
- 35th
- strongest of 39,637 since 1900
USGS ANSS Comprehensive Earthquake Catalog, event ushis816 (“3 km NW of Kalaoa, 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.
1
Aftershocks in 30 days
6.5
Largest aftershock, Oct 6, 1929 · its page
0
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.
- 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
1,799 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
- March 28, 1915M6.4
- August 20, 1924M5.0
USGS ANSS Comprehensive Earthquake Catalog. Local time is the time zone of the county nearest the epicentre. Magnitudes are as the catalogue reports them.