Archive for July, 2011

July 28, 2011

27072011 Hierro

130 Events, Energy Released 0.7093 tonnes of TNT
Hierro 27072011

July 27, 2011

26.07.2011 Hierro

120 Events, Energy Released 0.355 tonnes of TNT
Hierro 26072011

July 26, 2011

25072011 Hierro

71 Events, Energy Released 0.13388 tonnes of TNT
Hierro 25072011

July 25, 2011

24072011 Hierro

65 Events, Energy Released 0.090 tonnes of TNT
Hierro 24072011

July 24, 2011

23072011

136 Events, Energy Released 0.473 tones of TNT
Hierro 23072011

July 23, 2011

22072011 Hierro

202 Events, Energy Released 0.748 tonnes of TNT
Hierro 22072011

July 22, 2011

21072011 Hierro

108 Events, Energy Released 0.410 tonnes of TNT
Hierro 21072011

July 21, 2011

20072011 Hierro

11 Events, Energy Released 0.058 tonnes of TNT
Hierro 20072011

July 20, 2011

19072011 Hierro

3 Events, Energy released 0.0138 tonnes of TNT
Hierro 19072011

July 18, 2011

Hierro intro

The triangular island of Hierro is the SW-most and least studied of the Canary Islands.

The massive Hierro shield volcano is truncated by a large NW-facing escarpment formed as a result of gravitational collapse of El Golfo volcano about 130,000 years ago. The steep-sided 1500-m-high scarp towers above a low lava platform bordering 12-km-wide El Golfo Bay, and three other large submarine landslide deposits occur to the SW and SE. Three prominent rifts oriented NW, NE, and south at 120 degree angles form prominent topographic ridges.

The subaerial portion of the volcano consists of flat-lying Quaternary basaltic and trachybasaltic lava flows and tuffs capped by numerous young cinder cones and lava flows. Holocene cones and flows are found both on the outer flanks and in the El Golfo depression. Hierro contains the greatest concentration of young vents in the Canary Islands.

Uncertainty surrounds the report of an historical eruption in 1793.

Recent Activity (edit 27092011)
Instituto Geográfico Nacional (IGN) reported a drastic increase in the seismic activity at Hierro during 27 September-3 October, with more than 1,100 new seismic events detected, 83 of them felt by residents, with a maximum intensity value of IV using EMS-98 (European Macroseismic Scale). Most of the hypocenters were located offshore, SW of the island, at around 14 km depth. The maximum magnitude recorded during this week was 3.8. The total number of located events had reached more than 9,300 since the anomalous activity began on 16 July. The superficial deformation measured by the GPS network had reached 35 mm.