Spanish Earthquakes : A Weekly Update

 

Scientists observing the recent volcanic and seismic activity on the canary island of El Hierro have been witnessing less and less activity over recent weeks.

In the last 7 days alone (12.00 hrs Thurs 15th - 12.00 hr Thurs 22nd) 'just' 5 earthquakes were recorded on the Island, compared to as many as twenty activities per day being recorded less than two months ago.

The epicentres of the activities ranged from the town of Pinar to the North-West of the Island, to the El Golfo bay area off the coast of Frontera to the East of Pinar. Although fewer in number, the magnitudes were slightly higher than the average seen over recent weeks, varying between 2.0 and 2.8 on the richter scale*. However, the depths were sufficient that the effects were not felt by local residents, varying between 18 to 22kms.

As far as the underwater Volcanic eruption to the south of the island, in the Las Calmas bay area off the coast of La Restinga, is concerned, the activity appears to be subsiding with the jacuzzi decreasing in intensity, and the effect of the stain become less.

Although it would be foolish, and far too early, to speculate that this earthquake swarm was drawing to a close, it can be said with a reasonable degree of certainty that the volcanic ativity that was once threatened, is unlikely to effect the residents of the Island much more than it already has.

Tumbit Notes :

1.) Just what exactly is the difference when we hear scientists talk about the intensity of earthquakes being measured 'on the richter scale', and then data is given elsewhere noting that an earthquake measures 'on the MMS scale' ?

We have rumaged around and found a layman's answer to this question : The Moment Magnitude Scale (MMS) was devised in 1979 by scientists who found that the Richter scale only measured the strength of an earthquake's shockwaves and not the impact that it had on the surface.

So whilst the Richter scale measures seismic waves, or vibration, the MMS measures energy, or the distance of 'slip' between the fault, and the part of the surface unaffected by the quake.

MMS is generally only used as a measurement of earthquakes that are over 3.5 on the richter scale, any less and the effects on the surafce would be too low to measure.

2.) By comparison to the seismic activity on El Hierro that has been dominating the headlines of late, a total of 4 Earthquakes have also been recorded in Lorca, Murcia this last week.

Further to the two earthquakes measuring 4.5 and 5.2 on the Richter scale which caused devastation back in May, the latest 4 earthquakes occurred to the South-West of the Town earlier this week. Although the intensities were relatively low at between 1.5 - 2.9 on the Richter scale, their proximity to the surface meant that their effect was able to be measure on the MMS scale.

Tumbit Director, Dan Brammall, was in Lorca with family to celebrate the start of the Holiday period : "I was in Lorca shortly after the May earthquakes and like everyone else in the Town I am a bit nevous whenever I feel a shock. Monday's quake [2.9, 6km deep, MMS-4] was a little concerning, but the other three went largely unnoticed."

Read further news stories about the El Hierro Volcano by clicking the link HERE .