3.1 magnitude earthquake recorded off west coast of Lanzarote

Two earthquakes were recorded west and south-west of Lanzarote yesterday, Sunday 25th October, with the stronger measuring 3.1 magnitude on the Richter scale.

The larger tremor occurred at 6.08pm Canary Islands time, at an estimated depth of 50 kilometres, according to Spain’s National Geographic Institute, the IGN.

An earlier earthquake, measuring 2.6 magnitude, was recorded at 4.36am, at a depth of 31 kilometres. Its epicentre was further south-west.

Both were offshore, rather than immediately beside Lanzarote’s coastline. The IGN lists their location under the broad geographical label “Atlántico-Canarias”.

No damage or significant reports of people feeling the stronger earthquake had been reported.

Why do earthquakes happen around the Canary Islands?

The Canary Islands are volcanic islands, but earthquakes in the region can have different causes.

Some result from rocks moving along faults as stresses build up and are released underground. This is known as tectonic activity. Other tremors can be associated with the movement of magma or fluids beneath volcanic areas.

Earthquakes are regularly detected both beneath the islands and in the surrounding Atlantic. Many are too small, too deep or too far offshore to be noticed by residents and visitors.

One well-established area of seismic activity, known as the Inmedio Volcano, lies between Tenerife and Gran Canaria, although earthquakes also occur elsewhere around the archipelago.

Do these tremors mean an eruption is coming?

An earthquake on its own does not establish that an eruption is approaching.

Scientists assess the wider pattern: how frequently earthquakes occur, their depths and locations, and whether they are accompanied by changes such as ground deformation or unusual gas emissions.

The records checked for these two offshore events establish their timing, location, depth and magnitude. They do not, by themselves, identify the cause or demonstrate a developing volcanic emergency.

The two events should also not automatically be described as a main earthquake and an aftershock simply because they occurred on the same day.

The IGN’s measurements remain subject to revision as specialists review the recordings.