Volcanic tremor activity at El Hierro remains moderately elevated

November 18, 2011 – CANARY ISLANDS - The volcanic tremor measured at El Hierro remains at very high levels and in sharp contrast to visible activity, feeding speculations and fear about new volcanic vents opening up somewhere on or near the island. Some fear such a new vent could be located in the El Golfo Bay, near Frontera, since most of the (deep) earthquakes in recent days are concentrated beneath the northern sector of the island. However, so far, these earthquakes are very deep (ca. 20 km) and do not point towards an immediate eruption in this area, rather are intrusions of dykes in the upper mantle beneath the island. At La Restinga at the southern tip of the island, we could observe a slight increase in activity from the submarine vent ca. 1 km off the coast today: every 15-30 minutes, brownish plumes of water could be seen upwelling, flattening the ocean surface and sometimes producing dark stretches of floating mud(?) and foam (not steam!) in a circular area around the vents. The Instituto Volcanológico de Canarias (INVOLCAN) has been recording highly elevated levels of Helium and CO2 gas dissolved in the water around La Restinga, another sign that the submarine eruption is still in progress.

http://www.volcanodiscovery.com/view_news/2449/El-Hierro-volcano-Canary-Islands-Spain-intense-volcanic-tremor-and-speculations-about-possible-new-v.html