Underwater volcanic eruption continues off the coast of South El Hierro. Eruptive focus closer to the surface of the sea it was located about 150 meters deep. The result of the shallowness on Saturday October 15 began to see the first magmatic material at the sea surface, but stopped a few days after coming to the surface, presumably because the eruptive mouth closed.
The eruption of El Hierro launched at sea pyroclastic
These pyroclastic materials collected by the ships that have come to the point eruption and even coastal areas south of the island rocks are composed of two distinct visually.
Characteristics of the materials recovered from the eruption magmatic
These pyroclasts were formed out of lava 150 meters deep and 2.4 kilometers from the coast El Hierro. On the outside are black and round or oval shaped, but inside is a white, porous material, full of gas bubbles formed by the magma dragged from deeper zones.
The dark material is, according to a preliminary study of non-tip, a taquilita. This type of rock is a volcanic glass formed after rapid cooling of basaltic magma. As for the white material needed more comprehensive analysis.
What kind of volcanic eruption is El Hierro
In addition, the volcanic eruption of El Hierro is fissural type, which means that the lava does go outside along a fracture that can break the surface along a fissure or opening several more or less aligned mouths .
And that is the underwater eruption that takes place on the island of El Hierro appears to have several sources. According to official information would be at least three places that have gone lava and gases.
The lava eruptions of this type of flow with relative ease, ie that are not highly viscous lavas and are not in their composition a high percentage of silica. Basic lavas would.
Surtseyana eruption in El Hierro, the four phases
Also described the surtseyana like rash, by the eruption of Surtsey Island in Iceland. However, in this case the name refers to a volcanic eruption under water near the sea surface and this name affect the eruptive mouths found in shallower waters. The deeper pockets of the underwater eruption does not fall under this denomination.
These eruptions are characterized by four distinct phases. In the first volcanic materials are sea surface as bubbles of lava. Then appear a white column of steam to be followed by explosions caused by the underwater volcano and acquire darker shades. In the fourth stage would form a small island where there would be a fountain of lava that would expand until it ceased to exit.
In the current situation shallower focus of eruptive fissure eruption of El Hierro , which was located about 150 meters deep according to the information given by the PEVOLCA, seems to have closed, although the eruption may continue in deeper areas Building island of El Hierro. However, the volcanic tremor continued on CHIE seismic station that could precisely target the lava is coming out somewhere.
Possible evolution of the volcanic eruption in El Hierro
Thus, the published data on this volcanic phenomenon, although difficult to predict the possible evolution glimpse. The volcanic eruption of El Hierro could be stopped at any time, although in view of the deformation on the island is not expected to be the case in the short term.
It could also continue the rash known foci and in the case of the shallowest, and after passing through the phases of the eruption surtseyana, become an island, but for this last step came to an end would require a large input of magma from below.
If the contribution of magma is higher than the amount of lava that comes out of the different foci or if one of these will be closed for any reason, then it can happen that will open new eruptive mouths, either at sea or on land. If this happened in the sea in shallow areas may be mentioned earlier phases of the eruption surtseyana .
How could last eruption of El Hierro
In any case, the data of deformation and earthquakes in El Hierro which records the IGN, they have not stopped, at least reflect the geological process continues its course, and even may point to the arrival of more magma beneath the island. As for the duration of the volcanic phenomenon , David Calvo, non-tip, aimed at RTVE that could be extended in time but the important thing is the observation and monitoring of underwater eruption near the island to be opened from other sources if any.
Translated by Google. Written by Daniel Martin