Scientists who have been working around El Hierro believe the volcano that rumbles beneath the soil of the smallest island of the Canary Islands can hide a magma chamber bigger than Teneguía which erupted in La Palma, in 1971 . This conclusion was reached after complex mathematical calculations that lead them to have a real close approximation of what lies along the 12 km route where they believe the magma has accumulated over the past three months, Since the first detected earthquake swarm started in July. The Swarm had scientists from around the world watching the area closely.
On October 26, 1971 the Teneguía made an appearance in La Palma. The eruption lasted over 24 days, until 18 November and, according to studies, it is believed that drove about forty million cubic meters of magma. At that time, due to lack of technical means, nothing could be anticipated, but after the end of the eruption itself Scientists studied in detail the volcano and reached different conclusions. One was the amount of magma expelled.
Now, just 40 years later, scientists are based on the deformation suffered by the island in the last three months (about 5 centimeters) and in the path of the lava under the earth during that time (about 12 miles) that runs under El Hierro, are expecting the output will be near 50 million cubic meters of lava.
With this data on the table, the rash that breaks through at this time under the waters of the Sea Calm in La Restinga, could take between a month and a half, according to estimates calculated by the scientific community which moved to Meridian Island. Source