Man and Nature: Tremors in the Solomon Islands and North Korea, 6-12 February 2013

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Home / Man and Nature: Tremors in the Solomon Islands and North Korea, 6-12 February 2013
Earthquakes of M5.0 or greater 6-12 February 2013. Image credit: USGS

Earthquakes of M5.0 or greater 6-12 February 2013. Image credit: USGS

The movements of our dynamic planet over the past week make interesting reading. In bare numerical terms they certainly raise an eyebrow – although the total number of tremors recorded on the USGS real time earthquake map for the week isn’t significantly higher than might be expected, the top end of the magnitude scale shows an almost eye-popping difference.

The week saw 151 earthquakes of M5.0 or more (≥M5.0) – over four times as many as the previous week and almost ten times as many as the (admittedly quiet) week of 16-22 January.The explanation is an obvious one – a major earthquake and associated aftershocks in the Solomon islands (see below). If these are stripped out, the week has 21 shocks of ≥M5.0, by far the largest of which was an M6.9 in Colombia – the only earthquake outside the Solomon Islands cluster to exceed M6.0.

Largest Earthquake: M8.0 in the Solomon Islands

Earthquakes don’t conform to human-induced patterns, but statistics suggest than an earthquake of M8.0 or greater is to be expected just once or twice a year. The M8.0 which struck in the Solomon islands on 6 February, therefore, should be regarded as a major seismic event. The Solomon Islands lie close to a bend in the complicated margin between the Pacific and Australian plate, where numerous different motions interact.

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