New swarm of earthquakes started at El Hierro, Canary Islands

A new swarm of earthquakes started yesterday at El Hierro, Canary Islands. So far, almost 200 tiny quakes (none above magnitude 3 so far) have occurred in a broad N-S oriented area beneath the NE part of the island at around 18 km depth. 

A possible explanation includes a new magmatic intrusion at depth (magma accumulating at the lower crust-mantle boundary), Volcano Discovery reports.

Earthquakes at El Hierro recorded in last 3 days. Image credit: IGN

• Shaking, cracks and dangerous rockfalls from strong M 5.4 quake near El Hierro, Canary Islands (December 28, 2013)

"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." (GVP)

Featured image: GVP