El Hierro Earthquake : The swarm returns ?

Scientists for the National Geological Survey (IGN) observing seismic activity on the Canary Island of El Hierro have recorded in excess of 100 activities on the Island since midnight on Friday, with the strongest measuring 3.2 on the richter scale and at a depth of 24 km.

It is now more than 15 months since the Earthquake swarm on the Canary Island of El Hierro began to manifest itself.

The Island is home to more than 500 'open sky' Volcano cones, which means that seismic activity is something that the 10'000 residents of El Hierro are well used to. However, since the 16th of July of last year the National Geographic Survey (IGN) has recorded in excess of 30'000 earthquakes / tremors.

Activity over recent months had subsided after almost 12 months of tremors and earthquakes which had seen various stages of alert being issued by officials at various times.

Although the majority of activities were too slight and deep to be felt by residents on the Island's surface, on a number of occasions scientists registered over 1'000 activities per day.

The earthquakes have generally been clustered around the Frontera / Pinar area to the North-West of the centre of the Island, with depths averaging around 16km and with magnitudes averaging around 1.8 on the richer scale.

However, the activities have not been limited to earthquakes. On the southern side of the Island, off the coast of La Restinga, an underwater Volcano has spent the last 8 months producing magma some 300mt below the surface of the bay of 'Las Calmas'. Over recent month the resulting cone spread to a diameter of almost 700mts and with a height of 200mts and a crater of 120mts. The gases - dubbed a 'stain' by scientists - was mapped by NASA satellites, showing a dark green colour stretching for miles and at one point covering an estimated 34 hectares.

Three (vaguely) interesting points :

1.) 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 3.0 on the richter scale, any less and the effects on the surface would be too low to measure.

2.) The Canary Islands are Volcanic. A previous activity on the neighbouring Island of La Palma left behind an active Volcano clinging precariously to the side of the Island. Scientists have long speculated that even the slightest of seismic or volcanic activity could trigger an enormous landslide of such mass velocity that it would cause a Tsunami that would have the potential to devastate much of the eastern coast of North and central America.

The Youtube clip shows a good graphic depiction as to why so many conspiracy theorists have been so worried >>>

3.) Scientists recently confirmed that the activities over the past 12 months have caused the surface of the Island to have been distorted by as much as 5cms in places.

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