La Palma's volcano suddenly stopped erupting this morning - before restarting several hours later with 'explosions' heard miles away.
The brief hiatus, during which volcanic activity dropped off almost completely, sent scientists scrambling to work out what it means - amid warnings that the eruption is not over and could simply be entering another new phase.
Volcanologists theorised that a vent could have become briefly blocked or that underground channels may be shifting, possibly diverting lava elsewhere and opening up a new vent.
Meanwhile, new lockdown orders were issued for three areas today as lava that has already been expelled from the volcano continued to trickle towards the ocean.
Angel Victor Torres, president of the Canary Islands, said molten rock may reach the ocean 'within hours' where it will release a cloud of poison gas as it mixes with sea water - warning nearby residents to stay in their homes with their windows locked.
Those who are directly in the path of the lava flow have already been evacuated.
EU weather satellites captured the first clear image of La Palma's volcano without clouds on Sunday, showing the extent of the devastation it has caused
The volcano continued to erupt overnight Sunday but stopped around 10am Monday, with scientists scrambling to figure out why
A couple hold hands as they watch lava erupt from the La Palma volcano overnight Sunday, just hours before the eruption stopped
Scientists warn it is unlikely the volcano has stopped erupting for good, and may simply be gearing up for a 'big burst' later in the day
The new lockdown order covers the areas of San Borondon, Marina Alta, Marina Baja and La Condesa.
'Population will have to follow the authorities guidance and remain in their home with doors and windows closed,' the emergency services said on Twitter.
La Palma's new volcano, which is located on the Cumbre Vieja ridge on the south of the island, began erupting on September 19 and has been spewing out a continuous stream of lava and ash ever since.
Experts previously said the eruption could last between two weeks and three months, making Monday's shut-down unusual.
There have been periods of high and low activity since the eruption began, by Monday marked the first time it has stopped completely.
Geologist Nahum Mendez Chazarra told Spanish newspaper LaSexta that the volcano could simply be 'recharging' before a burst of activity.
David Calvo, of the Canary Islands Volcanological Institute, told La Vanguardia that another explanation could be that a vent has become blocked.
That could mean the maga is diverting to another part of the island, Mr Calvo added, pointing out that a cluster of earthquakes has been detected around 10 miles south of the eruption site today, close to the Teneguía volcano that erupted in 1971.
'It may be that there is a magma migration in the interior of the island... towards more accessible areas, or that there is a readjustment of the structure of the island in response to the exit of the magma.
'There is more magma,' he added. 'That it will
