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Sunday 28 October 2012

West Coast Canada Earthquakes update

From the WATCHERS site:


Strong aftershock M 6.3 struck Canada’s Queen Sharlotte Islands region – Aftershock list

The Watchers Tweet Tweet Canada’s Queen Charlotte Islands region struck strong aftershock at 18:54 UTC on October 28, 2012 according to USGS. This is still preliminary magnitude but the event was reviewed by seismologist. Epicenter was located 159 km (98 miles) SSW of Masset, Canada at coordinates 52.633°N, 132.701°W. Recorded depth was 8.2 km (5.1 miles). EMSC reported this earthquake as magnitude 5.8 with depth of 5 km.   Magnitude 6.3 Date-Time Sunday, October 28, 2012 at 18:54:21...
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Canada’s Queen Charlotte Islands region struck strong aftershock at 18:54 UTC on October 28, 2012according to USGS. This is still preliminary magnitude but the event was reviewed by seismologist. Epicenter was located 159 km (98 miles) SSW of Masset, Canada at coordinates 52.633°N, 132.701°W. Recorded depth was 8.2 km (5.1 miles).
EMSC reported this earthquake as magnitude 5.8 with depth of 5 km.

Magnitude6.3
Date-Time
  • Sunday, October 28, 2012 at 18:54:21 UTC
  • Sunday, October 28, 2012 at 11:54:21 AM at epicenter
Location52.633°N, 132.701°W
Depth8.2 km (5.1 miles)
RegionQUEEN CHARLOTTE ISLANDS REGION
Distances159 km (98 miles) SSW of Masset, Canada
245 km (152 miles) SW of Prince Rupert, Canada
343 km (213 miles) SW of Terrace, Canada
595 km (369 miles) WNW of Campbell River, Canada
Location Uncertaintyhorizontal +/- 18.5 km (11.5 miles); depth +/- 6.5 km (4.0 miles)
ParametersNST=281, Nph=281, Dmin=317.3 km, Rmss=1.32 sec, Gp= 83°,
M-type=regional moment magnitude (Mw), Version=8
Source
  • Magnitude: USGS NEIC (WDCS-D)
    Location: USGS NEIC (WDCS-D)
Event IDusb000dg06

Mainshock details

Magnitude7.7
Date-Time
  • Sunday, October 28, 2012 at 03:04:10 UTC
  • Saturday, October 27, 2012 at 08:04:10 PM at epicenter
Location52.769°N, 131.927°W
Depth17.5 km (10.9 miles)
RegionQUEEN CHARLOTTE ISLANDS REGION
Distances139 km (86 miles) S of Masset, Canada
202 km (125 miles) SSW of Prince Rupert, Canada
293 km (182 miles) SW of Terrace, Canada
556 km (345 miles) NW of Campbell River, Canada
Location Uncertaintyhorizontal +/- 14 km (8.7 miles); depth +/- 4 km (2.5 miles)
ParametersNST=716, Nph=716, Dmin=267.2 km, Rmss=0.95 sec, Gp= 58°,
M-type=regional moment magnitude (Mw), Version=A
Source
  • Magnitude: USGS NEIC (WDCS-D)
    Location: USGS NEIC (WDCS-D)
Event IDusb000df7n

Tectonic summary by USGS

The October 28th, 2012 (October 27 at the location of the epicenter) M 7.7 earthquake south of Masset, Canada, occurred as a result of oblique-thrust faulting near the plate boundary between the Pacific and North America plates. At the location of this event, the Pacific plate moves approximately north-northwest with respect to the North America plate at a rate of approximately 50 mm/yr.This earthquake is likely associated with relative motion across the Queen Charlotte fault system offshore of British Columbia, Canada. Studies of tectonics in this region suggest plate motions are taken up by strike slip faulting parallel to the plate boundary, accompanied by lesser amounts of thrust motion to accommodate the oblique nature of the plate motion vector between the two plates with respect to the orientation of the main plate boundary fault structure. This oblique component of plate motion may involve either underthrusting of the western edge of the Pacific Plate beneath North America, or be taken up on crustal faults within the North America plate. The October 28th earthquake is consistent with either scenario. Its rupture extended approximately 100-150 km along strike, along the shallow extent of the source fault. Slip amounts reached approximately 5m, in a patch to the south of the epicenter. Aftershocks delineate the rupture well, as shown here.
This region of the Pacific:North America plate boundary has hosted 7 earthquakes of magnitude 6 or greater over the past 40 years – the largest of which was a M 6.6 earthquake in 2009, 80 km to the south east of the 2012 earthquake. In 1949, a M 8.1 earthquake occurred closer to the Pacific:North America plate boundary, likely as a result of strike-slip faulting, approximately 100 km northwest of the October 28th earthquake, near the northern extent of Haida Gwaii region (formerly Queen Charlotte Islands). Summary report.

Aftershock list

1 comment:

  1. We must always be ready in all times because we don't know where and when the earthquakes like this will occur.

    Check out the latest news about earthquake here-->http://newsinfo.inquirer.net/tag/earthquake

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