Here is the Keele seismogram for the M7.3 Columbia earthquake of September 30, 2012. As it is a subduction zone earthquake about 150km deep, note the lack of surface waves and consequent limited damage from such an event.
More details from the USGS.
Two earthquakes in Northern Italy this morning, showing up well on our helicorder trace at Keele University (above).
The larger first event was magnitude 6.0 and has unfortunately caused a number of fatalities.
The second 5.2 magnitude aftershock is obviously not quite as distinct.
More details from the BBC
Two large earthquakes this morning offshore Sumatra, an 8.6 followed by a magnitude 8.2 a couple of hours later. Fortunately, both strike-slip in mechanism so no significant tsunami.
Here are the seismograms from our schools seismometer here at Keele University UK.
Twenty-four hour record
Magnitude 8.6 08:38 11/04/2012
Magnitude 8.2 10:43 11/04/2012
Another Stoke-on-Trent earthquake, magnitude 1.8 occurred yesterday (January 19, 2012) provisionally located near the village of Bagnall, similar to the earthquake on January 11. Above is the recording from Keele University.
If the location of these two events remain this far east, I may have to revise my initial assessment that they are coal mining related since this area is outside the Coal Measures subcrop.
Recent Stoke-on-Trent Earthquakes
View Stoke Quakes in a larger map
Yesterday Stoke-on-Trent experienced a minor, magnitude 2.4 tremor that we picked up on our seismometer at Keele.
I think that the official location, near Light Oaks, is a bit too far east as it is almost certainly a former coal mining induced event and the main coal measure sequence is further west. It will be interesting to find out where the felt reports come from.
We haven’t had earthquakes in the north of the city since the Smallthorne sequence of 1988-1990.
It is interesting that we have coal mining induced events of this size and nobody turns a hair, however, if it had been shale gas extraction related, the world would be about to end.
