Archive for August 27th, 2012

August 27, 2012

Hiroo District, Hokkaido Prefecture, Japan 5.8Mw, 25/08/2012

A Strong 5.8Mw earthquake has occurred on the island of Hokkaido, Japan, located by JMA at the headwaters of the Rakko-gawa River east-north-east of 1457m high Mt Tokachi in the Hiroo District.

JMA Preliminary

Lat/Long: 42.3 143.1
UTC: 25/08/2012 14:16:15
JST: 25/08/2012 23:16:15
Depth: 50
Mag: 5.9 ML
Location: Hokkaido Prefecture, Hiroo District, Maruyamadoriminami
Status: Preliminary
Energy Released: 10,675.994 tonnes of TNT
Source: JMA (25.08.2012)

JMA Final

Lat/Long: 42.328 143.111
UTC: 25/08/2012 14:16:17
JST: 25/08/2012 23:16:17
Depth: 49.1
Mag: 6.1 ML
Status: Final
Energy Released: 21,301.409 tonnes of TNT
Source: JMA (02.09.2012)

NIED Hi-net  put in a late entry with more precise details, the magnitude at 6.6ML
JST: 23:16:16.836
Lat/Long: 42.3079, 143.1654
Depth: 57.7km
However since NIED Hi-net is as preliminary and automatic report, you have to refer to the formal information released by the JMA by default.

In the interactive map below click on Icon for event details.
To view a larger map and list (in decending order of occurance), click on text “View Larger Map” below map.

Aftershock map

(Final locations)


gfz moment tensor solution


to 27/08/2012 03:09:50.8UTC
mag1= 77 , mag2= 14, mag3= 9
mag4= 0 , mag5= 0 , mag6= 1 (mainshock)
total= 101 (incl. main shock)
total energy released= 21,315.256 TTNT

Network Plots

Network estimates of the location of the main shock
JMA= Japan Meteorological Agency [2]
(orange icon is preliminary location, red icon is the final location)
NIED= National Research Institute for Earth Science and Disaster Prevention
RAS= Russian Academy of Sciences
EMSC= European Mediterranean Seismological Centre
GFZ= GEOFON Program, Potsdam, Germany
UGS= United States Geological Survey
GCMT= Global Centroid-Moment-Tensor Project

History 1962-2012 (ANSS)

Historical events within a 100km radius of todays event. Data from the Advanced National Seismic System catalog hosted by the Northern California Earthquake Data Center.

Zoom in and see there was a 5.1 on 15/03/1993 03:35:06 just 100 meteres from todays event at similar depth of 55.5km.

Todays event marked with a number 1.

Timeline Graph

72 hour Aftershock Timeline Graph ( magnitude versus time) for the Hidaka Mountains, Hokkaido Prefecture, Japan, 6.1ML (5.8Mw) 25/08/2012 earthquake based on data from the Japan Meteorological Agency
72 hour Hidaka Mountains, Hokkaido, Japan, 6.1ML Aftershocks Graph