An earthquake measuring 4.1 on the Richter scale shook El Hierro island in Spain's Canaries on Monday, the strongest of hundreds of tremblors recorded in recent days in the territory which suffered an undersea volcanic eruption in 2011, Spain's National Geographical Institute said Monday.

The earthquake struck at 3:41 pm (1441 GMT) and its epicentre was in the Atlantic Ocean about 12 kilometres (7.5 miles) west of the island, a spokesman for the institute said. It was measured at a depth of 16 kilometres and was preceded by another earthquake measuring 4.0 on the Richter scale.

About 800 earthquakes have been recorded in El Hierro, which has about 10,000 inhabitants, since March 18, the spokesman added.

The majority have measured above 2.0 on the Richter but only a handful have been strong enough for people on the island to notice.

In October 2011 an underwater volcano erupted off the coast of El Hierro, two days after an earthquake measuring 4.3 on the Richter scale rocked the island.

El Hierro, which means "Iron" in Spanish, suffered thousands of earthquakes throughout much of 2011, only a few of them, prompting officials to briefly close a tunnel linking the island's two main towns -- Frontera and Valverde -- and evacuate dozens of people over fears of landslides.

The Canary Islands are located off the northwestern coast of Africa. El Hierro, which has an area of just 267 square kilometres (103 square miles) is the westernmost of the seven islands of volcanic origin that make up the archipelago.

The last major volcanic eruption off the Canary Islands happened off Teneguia, Las Palmas, in 1971.