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El Hierro volcano
shield volcano 1500 m
Canary Islands (Spain), 27.63°N / -17.99°W
Current status: dormant (1 out of 5)
El Hierro webcams / live data
El Hierro volcano books | Tours
El Hierro volcano eruptions:
2012 (?) (probable second submarine eruption in June-July west of the island), 2011-12 (Oct-Mar, submarine eruption near La Restinga), 1793
Typical eruption style:
mainly effusive, basaltic fissure eruptions
Last earthquakes nearby
El Hierro volcano tours
Europe's Volcanic Outpost (Tour to the Canary Islands: Lanzarote, La Palma, El Hierro and Tenerife)

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El Hierro volcano - archived updates Mar-Nov 2013

Update Thu 03 Oct 18:58
Map of recent quakes at El Hierro
Map of recent quakes at El Hierro
Depth vs time of earthquakes during the past 7 days
Depth vs time of earthquakes during the past 7 days
A small earthquake swarm under the center of the island, at about 12 km depth, occurred on 30 Sep.
Small earthquakes continue
Update Fri 06 Sep 16:40
Map of recent earthquakes under El Hierro (IGN)
Map of recent earthquakes under El Hierro (IGN)
Depth vs time of earthquakes during the past 7 days
Depth vs time of earthquakes during the past 7 days
Earthquake activity remains elevated, although most quakes are extremely small and not felt. The area of the hypocenters is about 10 km below the central part of the island.
Update Fri 30 Aug 12:09
Location of quakes during the past 2 weeks (IGN)
Location of quakes during the past 2 weeks (IGN)
Current tremor signal (CHIE station, IGN)
Current tremor signal (CHIE station, IGN)
Small earthquakes (mostly below magnitude 2) continue to occur frequently (10-20 per day), mostly under the central part of the island. Right now, this activity seems to be picking up, but it is too early to see if this evolves into another swarm.
Update Wed 14 Aug 17:13
Earthquake activity has been calmer today. So far, only 9 tiny quakes (all below magnitude 2) have been recorded under the island.
New seismic swarm ?
Update Tue 13 Aug 17:21
Map of recent earthquakes under El Hierro (IGN)
Map of recent earthquakes under El Hierro (IGN)
Depth vs time of earthquakes during the past 7 days
Depth vs time of earthquakes during the past 7 days
The number of earthquakes has increased from averages of 5-10 to about 30 during the past few days. The location of the recent quakes is in a N-S elongated layer about 10-12 km depth in the western part of the island under the El Golfo bay. So far, no quakes above magnitude 3 have occurred.
Update Sun 14 Jul 04:27
Location of quakes during the past 2 weeks (IGN)
Location of quakes during the past 2 weeks (IGN)
Depth vs time of earthquakes during the past month
Depth vs time of earthquakes during the past month
Small clusters of earthquakes continue to occur in two areas, at 10-20 km depth, one located beneath the central area of the island and the second under an area off the western tip. Overall, seismic activity has remained low and shows a decreasing trend over the past months.
Volcano remains calm
Update Wed 12 Jun 16:53
Location of quakes during the past 2 weeks (IGN)
Location of quakes during the past 2 weeks (IGN)
Depth vs time of earthquakes during the past month
Depth vs time of earthquakes during the past month
Seismic activity of the island has been calm over the past weeks. The number of daily small earthquakes continues to be weakly elevated, with hypocenters clustered under the central and western parts of the island.
4.1 earthquake
Update Thu 11 Apr 18:44
Location of this afternoon's M4.1 quake
Location of this afternoon's M4.1 quake
A relatively strong earthquake of magnitude 4.1 occurred at 5:26 GMT this afternoon, west of the island at 19 km depth. So far, it has been an isolated event.
Situation calm
Update Wed 10 Apr 09:49
Map of recent earthquakes at El Hierro (IGN)
Map of recent earthquakes at El Hierro (IGN)
Current seismic signal (IGN)
Current seismic signal (IGN)
Time and depth of recent earthquakes
Time and depth of recent earthquakes
Earthquake activity has remained low, but there are still a few smaller quakes scattered under the island. This could be related to residual stress release caused by the relatively strong deformation the western part of the island experienced during the recent swarm.
New earthquakes ?
Update Mon 08 Apr 17:18
Depth vs time of recent earthquakes under El Hierro
Depth vs time of recent earthquakes under El Hierro
Current seismic signal (IGN)
Current seismic signal (IGN)
GPS-measured deformation at some stations at El Hierro (IGN)
GPS-measured deformation at some stations at El Hierro (IGN)
After being almost completely calm for several days, earthquake activity has again picked up during the past 48 hours (and is showing an increasing trend), but the intensity and frequency of quakes is (so far) nothing compared to the latest swarm two weeks ago. The largest event so far was a mag 3.0 quake 15 km west of the island, at 13 km depth. Inflation has halted and now shows a weak trend to deflation.
Update Fri 05 Apr 17:23
Distribution of earthquakes during the recent crisis at El Hierro (IGN)
Distribution of earthquakes during the recent crisis at El Hierro (IGN)
Current seismic signal (IGN)
Current seismic signal (IGN)
No further significant earthquake activity has occurred since the last pulse on Wednesday. It becomes more and more likely that the crisis (or, if that is was what caused it, the magmatic intrusion under western El Hierro) has ended. Deformation (inflation and horizontal displacement to the east) has eased a lot. For the vertical movement, the strong inflation has stopped or even began to show a trend of deflation.
End of the seismic crisis ?
Update Thu 04 Apr 10:40
Current seismic signal (IGN)
Current seismic signal (IGN)
Seismic signal yesterday (IGN)
Seismic signal yesterday (IGN)
Depth vs time of recent earthquakes under El Hierro
Depth vs time of recent earthquakes under El Hierro
Earthquake activity has continued to calm down and only few and weaker quakes have occurred since yesterday. Whether this is a pause or (more likely) the gradual ending of the latest seismic crisis will likely be seen in the next days.
Stronger earthquakes again
Update Wed 03 Apr 08:05
Current seismic signal (IGN)
Current seismic signal (IGN)
A series of stronger earthquakes has occurred earlier today, including two felt quakes at about 20 km depth of magnitudes 4.2 and 4.5. The epicenters were in the same area as previously, about 10-15 km to the west of the island.
Relatively calm day for El Hierro
Update Tue 02 Apr 17:07
Current seismic signal (IGN)
Current seismic signal (IGN)
Left: anomalies around the submarine cone; right: anomalies over time (IEO)
Left: anomalies around the submarine cone; right: anomalies over time (IEO)
So far, it has been one of the calmest days during the now two-weeks-long seismic crisis. Tremor has been more or less absent today, while earthquakes (so far today: 34 quakes between magnitudes 1.6-3.2) have continued at reduced intensity.
Given the past experience, it is certainly too early to draw a good conclusion whether we are near the end of the crisis (or the suspected magma intrusion) or just in a pause, while magma is potentially building up new pressure.

Recent oceanographic studies at La Restinga:
In the meanwhile, the Instituto Español de Oceanografía (IEO) has published some preliminary results of the just ended campaign of the Ramón Margalef research vessel around the new submarine volcanic cone that formed during the 2011-12 eruption. In the vicinity of its surface, among many other parameters measured, elevated pH values (7.4 vs the normal of 6.9), increased salinity and anorganic (volcanic) CO2 content were found.
More (in Spanish) at this link.
Update Tue 02 Apr 09:40
Depth vs time of recent earthquakes under El Hierro
Depth vs time of recent earthquakes under El Hierro
Current seismic signal (IGN)
Current seismic signal (IGN)
Seismic signal yesterday (IGN)
Seismic signal yesterday (IGN)
The seismic swarm has continued to decrease and activity is currently low. So far, IGN lists about 10 quakes above magnitude 1.5 for today, the largest a magnitude 3.3 at 02:32 GMT at 20 km depth. Yesterday: 82 earthquakes between M 1.7 - 3.8.
Earthquakes continue, but weaker today
Update Mon 01 Apr 18:30
Location of quakes during the past 48 hours at El Hierro
Location of quakes during the past 48 hours at El Hierro
Current seismic signal (IGN)
Current seismic signal (IGN)
The situation has been a bit calmer today, with still continuing earthquakes, but their frequency and strength has become less compared to yesterday (when there were two earthquakes of magnitude 4.5 and 4.9.) Tremor pulses also have become weaker and shorter, and currently, tremor is near absent. Whether this means that the end of the crisis is slowly approaching remains to be seen.
Update Sun 31 Mar 13:47
Location of the magnitude 4.9 quake
Location of the magnitude 4.9 quake
Current seismic signal (IGN) - the strong black signal is the 4.9 quake at 11:00 GMT
Current seismic signal (IGN) - the strong black signal is the 4.9 quake at 11:00 GMT
IGN places the earthquake that just occurred also at magnitude 4.9, but at the "usual" 20 km depth and in the "usual" area about 10 km west of the island. So far, this has been the strongest quakes during the whole crisis! Fortunately, the earthquake struck at depth and beneath the sea relatively far from the island where it was still widely felt. The risk of rockfalls in areas with steep cliffs (most of the western part of the island) is elevated. People should stay away from cliffs and unstable rock faces!
Strong magnitude 4.9 earthquake at 10 km depth
Update Sun 31 Mar 13:45
A (for El Hierro) powerful earthquake has just occurred; EMSC places it at magnitude 4.9 and depth at 10 km with a location off to the north of the island. These data are preliminary. IGN's more detailed earthquake information might correct this, but the website (probably due to intense traffic) was not accessible.
Update Sun 31 Mar 12:12
Current tremor signal (IGN)
Current tremor signal (IGN)
Location of recent quakes at EL Hierro (IGN)
Location of recent quakes at EL Hierro (IGN)
Happy Easter to all! However, Easter Sunday on El Hierro is all but quiet: although volcanic tremor has dropped, earthquakes in an area about 10 km west off the island continue. Some of them are strong - a new magnitude 4.5 event just occurred less than an hour ago. The low, or almost absent tremor at the moment could indicate that magma for now is stagnating at depth (about 20 km) and building up pressure again to open new cracks and move again. - Yesterday's earthquake count: 129 (only quakes >M1.3) - Deformation has started to slow down a lot for now.
Update Sat 30 Mar 09:50
Location of recent quakes at EL Hierro (IGN)
Location of recent quakes at EL Hierro (IGN)
Current seismic signal (IGN)
Current seismic signal (IGN)
The situation to the west of the island had not changed much and the islanders are in for an uneasy Easter weekend: the seismic swarm continues with frequent and increasingly strong earthquakes and tremor pulses. 15 quakes with magnitudes between 4-4.7 were recorded yesterday alone, the total number of quakes is in the hundreds. A further migration of the hypocenters to the south can be seen, and most quakes remain in the 18-20 km depth layer, with a few in the upper layer at about 10-12 km depth. Infation has slowed down a bit, but reaches now 12 cm in the western part of the island itself. If the seismic swarm, inflation and increased CO2 emissions are indeed caused by fresh magma intruding (the most commonly accepted interpretation, but nobody can be 100% sure about that), it is currently pooling at the base of the island's crust and slowly making its way in horizontal rather than vertical directions. Apparently, magma has not started (yet) to penetrate the island's volcanic edifice with vertical dikes, but this could change quickly, in which case another submarine eruption would be expected.
Magnitude 4.6 earthquake
Update Fri 29 Mar 10:40
Location of this morning's M4.6 earthquake (IGN)
Location of this morning's M4.6 earthquake (IGN)
Seismic signal showing lots of strong quakes (including a M4.6 at 08:14) between 8-9am (IGN)
Seismic signal showing lots of strong quakes (including a M4.6 at 08:14) between 8-9am (IGN)
Another large quake of magnitude 4.6, which was widely felt on the island, just occurred at 08:14 GMT at 18 km depth about 10 km west of the island under the seabed.
Earthquakes increase again, magnitudes>4
Update Fri 29 Mar 08:38
Map and location of recent quakes at El Hierro (IGN)
Map and location of recent quakes at El Hierro (IGN)
Current seismic signal (IGN)
Current seismic signal (IGN)
The situation has not changed much. Pulsating tremor and strong earthquakes up to magnitudes 4.3 continued throughout the night and have intensified this morning. A further small migration towards the south can be noted. Most quakes remain in the layer at 18-20 km depth.
Deformation (uplift and eastwards displacement) continue as well, although at somewhat reduced rate, and has reached 12 cm in the parts of western El Hierro.
- Yesterday's earthquake count: total listed (>mag 1.4):185, >mag 3: 47
- Today so far: 24 (including 3 quakes >mag. 4)
Depth vs time of yesterday's quakes under El Hierro
Depth vs time of yesterday's quakes under El Hierro
Seismic swarm continues
Update Thu 28 Mar 16:50
Map of recent earthquakes at El Hierro (IGN)
Map of recent earthquakes at El Hierro (IGN)
The earthquake swarm continued with no signs of ending soon. So far, 119 earthquakes (including 32 quakes >=M3, and one of magnitude 4.1) have been recorded today.
Their location has migrated a bit to the south and to a bit greater depths than before (16-18 km mostly). A few weaker quakes have also been recorded at lower depth of 7-10 km, possibly related to release of stress caused by the strong deformation, rather than intruding magma.
Increased CO2 emission supports magma intrusion is happening
Update Thu 28 Mar 14:01
Diffuse CO2 emission for El Hierro (INVOLCAN)
Diffuse CO2 emission for El Hierro (INVOLCAN)
The latest CO2 measurements show a significantly higher than normal level of gas emission, consistent with fresh magma arriving from deeper sources. INVOLCAN has released the following graph comparing current levels (1684 ± 72 tons of CO2 per day) with measurements during the previous eruptions and crises.
Unfortunately, there is a large data gap for the past months.
Source: INVOLCAN
Update Thu 28 Mar 12:22
Current seismic signal (IGN)
Current seismic signal (IGN)
Depth vs time of recent quakes under El Hierro
Depth vs time of recent quakes under El Hierro
Another strong pulse of tremor and earthquakes (including a felt 3.8 magnitude event a short time ago) is in progress. The hypocenters of quakes have "dived" to 18-20 km depth, which could suggest a new batch of magma arriving from depth.
Rockfalls on the island and "Yellow Alert" for western El Hierro
Update Thu 28 Mar 09:36
Location of recent quakes at EL Hierro (IGN)
Location of recent quakes at EL Hierro (IGN)
Current seismic signal (IGN)
Current seismic signal (IGN)
The intensity of the ongoing earthquake swarm has again decreased somewhat although a strong pulse of tremor and quakes occurred 2 hours ago.
The latest quakes, mostly in the magnitude 2-3 range and at about 18 km depth show a migration of hypocenters to the south to an area about 10 km west of the island, indicating that magma has moved to there now.
- Yesterday's earthquake count: 48 quakes >= M2.8, including 6 magnitude 4+ quakes
- Today so far: 17 quakes between M3-4
- Deformation has reached 11 cm uplift and eastward displacement in parts of Western El Hierro. This is consistent with the intrusion of a magma body at the western base of the volcanic edifice. The latest data points on IGN's charts (see El Hierro data & webcams) suggest that the deformation has started to slow down, however.

From the overall distribution of earthquakes, it appears that there are two zones where they have been occurring, one at a layer at 10-13 km depth, and a deeper one at about 15-20 km depth. Still, no magmatic intrusion seems to have significantly penetrated the crust composed of the volcanic edifice itself.
Rockfalls:
During the more intense phases in the past days, with earthquakes as strong as 4.6, many rockfalls have been noted from the steep cliffs in the western part of the island, in particular along the road Frontera-Sabinosa. PEVOLCA has now declared "Yellow Alert" for the western part of El Hierro and advises the population to stay away from steep cliffs.
3D animation of the 2011-2012 submarine volcano:
The Istituto Oceanografico has released a 3D animation of the new volcanic cone formed in 2011-12, using the new data obtained by the latest bathymetry mission of the Oceanographic Vessel Ramon Margalef:

Earthquakes increase again, magnitudes>4
Update Wed 27 Mar 18:18
Current tremor signal (IGN)
Current tremor signal (IGN)
Map of today's earthquakes at El Hierro (the larger circles are magnitude 4 quakes)
Map of today's earthquakes at El Hierro (the larger circles are magnitude 4 quakes)
Depth vs time of today's quakes under El Hierro
Depth vs time of today's quakes under El Hierro
After a day of weakened activity, the seismic swarm has increased with higher energy tremor and stronger earthquakes than ever. Hundreds of earthquakes have occurred so far, including about 25 > magnitude 3 and no less than 4 above magnitude 4 (M4.1-4.6). It seems plausible that magma has once again built up pressure and has broken new fractures into the low crust beneath the NW part of the volcanic edifice. Many quakes are now at 11-15 km depth, i.e. the epicenters, or the likely present location of the intruding magma, has perhaps started to rise. The likelihood of a new eruption in a possible near future thus once again increased.
Seismic swarm weakens
Update Wed 27 Mar 13:13
Current tremor signal (IGN)
Current tremor signal (IGN)
The earthquake swarm has slowed down a bit, but continues with more than 70 quakes > magnitude 2 so far today, in a similar area as yesterday at depths mostly around 15 km. Tremor has weakened for the time being. This could either suggest that magma is currently stagnating and building up pressure (in which case a few stronger quakes could be expected) or that magma supply is slowly easing. It is certainly to early to draw any conclusions.
Earthquakes continue, increasing inflation
Update Tue 26 Mar 16:40
Depth vs time of today's quakes under El Hierro
Depth vs time of today's quakes under El Hierro
GPS-measured deformation at some stations at EL Hierro (IGN)
GPS-measured deformation at some stations at EL Hierro (IGN)
Earthquakes (more than 120 > M2 today so far) and volcanic tremor continue to be intense, and inflation has reached 10 cm on stations (HI05) located in western El Hierro.
The foci of the quakes remains at about 15 km depth 5-10 km NW off the western top of the island, i.e. at the boundary to the crust beneath the island, suggesting that the still moving magma is for now not rising siginficantly into the harder layers that compose the islands' edifice. Whether and when this changes, i.e. magma starts to move vertically towards an eruption, is impossible to day, but a real possibility.
Update Tue 26 Mar 09:38
Location of recent quakes at EL Hierro (IGN)
Location of recent quakes at EL Hierro (IGN)
Current seismic signal (IGN)
Current seismic signal (IGN)
The situation has not changed much. The seismic swarm continues with pulsating medium to strong tremor and frequent earthquakes, in more or less the same area as yesterday, 5-10 km NW off the island at depths mostly between 13-20 km. The average magnitudes of quakes has continued to increase: yesterday alone, there were almost 50 earthquakes >magnitude 3 - probably a record number for El Hierro, including 2 quakes of M4 and 4.1. This trend is continuing today. A rough interpretation could be that the magma intruding into new fractures at depth is encountering higher resistance and is building up more pressure before the rock breaks.
Update Mon 25 Mar 08:17
Map of today's earthquakes (more than 50 quakes above mag 2, about 20 quakes >M3, and one  of M4)
Map of today's earthquakes (more than 50 quakes above mag 2, about 20 quakes >M3, and one of M4)
Depth vs time of today's quakes
Depth vs time of today's quakes
Current seismic signal
Current seismic signal
The likelihood of a new submarine eruption in the near future is increasing. Earthquakes and pulsating strong tremor continued with little changes, indicators of magma intruding into new dikes in the western rift zone. There is also a trend towards stronger quakes (about 20 magnitude 3+ events including a M4 this morning) and shallower earthquakes (many at around 11-12 km depth today). This suggests that magma is slowly breaking pathways upwards, i.e. towards the seafloor. The area has remained about 5 km off shore NW from the western tip of the island, ie. under the submarine prolongation of the volcano's western rift zone. This is where now a new eruption should be expected, if the magma does not decide to migrate laterally once again.
List of some of today's quakes with depths around 11-12 km
List of some of today's quakes with depths around 11-12 km
Update Sun 24 Mar 16:05
Current seismic signal (IGN)
Current seismic signal (IGN)
Depth vs time of today's quakes under El Hierro
Depth vs time of today's quakes under El Hierro
The earthquake swarm continues with little changes. Most epicenters have remained in an area at about 15-17 km depth a few km NW off the western tip of the island. Volcanic tremor, suggesting magma movements, is continuous with strong pulses every few hours.
Earthquake count today (only magnitudes >2): 111
Update Sun 24 Mar 11:02
Current tremor amplitude (IGN)
Current tremor amplitude (IGN)
A strong pulse of volcanic tremor has started, accompanied by a 3.2 magnitude quake at 15 km depth at 09:40 GMT.
It seems that magma is continuing to move, and the scenario of a possible new eruption is becoming more and more likely.
Some of the earthquakes listed are quite shallow (few km), but they are most likely a result of tectonic adjustments caused by the ongoing inflation (about 5 cm so far for the western parts of the island).
Update Sun 24 Mar 10:07
Map of recent earthquakes at El Hierro (IGN)
Map of recent earthquakes at El Hierro (IGN)
Current tremor signal (IGN)
Current tremor signal (IGN)
The situation has remained stable, tremor has eased a bit, possibly either because the flow of magma has been lower or because its is currently blocked. - 23 earthquakes (>mag 2) so far today - earthquake epicenters around 16-17 km, in the same area to the NW of the island's western tip.
Earthquakes increasing in frequency and magnitude
Update Sat 23 Mar 22:44
Current tremor signal (IGN)
Current tremor signal (IGN)
Depth vs time of today's quakes under El Hierro
Depth vs time of today's quakes under El Hierro
The seismic swarm continues with even increasing intensity, as to both the average magnitude and frequency of earthquakes, as well as amplitude of harmonic volcanic tremor which is oscillating between higher and lower phases. This might correspond to some sort of "stop and go" behavior of magma moving its way through new cracks in the lower crust beneath the island. The location of the epicenters of quakes, the presumed location of the current magma intrusions, is now about 5 km NW of the western tip of the island, and at depths between 10-17 km. No strong upwards trend is yet visible, but this could change quickly.
Today's earthquake count so far:
- 155 earthquakes > mag 2
- including 15 between M3-3.5
Earthquakes continue with increasing magnitudes
Update Sat 23 Mar 16:41
Map of recent earthquakes at El Hierro (IGN)
Map of recent earthquakes at El Hierro (IGN)
Current tremor signal (IGN)
Current tremor signal (IGN)
Deformation measured at GPS stations 3-5 (in the western part of the island)
Deformation measured at GPS stations 3-5 (in the western part of the island)
The scenario of an eruption in the near future is becoming increasingly likely:
- Volcanic tremor continues, suggesting magma is still moving although mostly laterally for the time being to an area just north off the western tip of the island.
- Earthquakes continue at high frequency and increasing magnitudes (more than 90 quakes above magnitude 2, including 8 of magnitudes 3-3.5 so far today). Their epicenters have remained at 14-16 km depth mostly, with some shallower events as well.
- Deformation of the western part of the island continues to increase, with vertical uplift reaching about 5 cm on some stations in the westernmost part of the island.
The Spanish research vessel Roman Margaleff is on its way to investigate the area offshore western El Hierro, and INVOLCAN is planning a field survey in the coming days. Their results will likely give more clues about what is going on.
Update Fri 22 Mar 17:16
Map of today's earthquakes at El Hierro
Map of today's earthquakes at El Hierro
Current tremor signal (IGN)
Current tremor signal (IGN)
Earthquakes and tremor have continued through the day, and continued to migrate a bit to the NW off the NW tip of the island. So far, 62 quakes above magnitude 2 have been recorded today. In addition, the average depth of the latest earthquakes has become a bit shallower and is now around 13 km (compared to 17-20 km before). This suggests that magma is still moving and has risen a bit closer to the surface, and, thus, a possible eruption.
3rd pulse of earthquakes, including magnitude 3.8 quake at 15 km depth
Update Fri 22 Mar 06:50
Map of recent earthquakes at El Hierro
Map of recent earthquakes at El Hierro
Current tremor signal (IGN)
Current tremor signal (IGN)
Tremor signal yesterday
Tremor signal yesterday
GPS data (North/East/verstical displacement) by IGN; station HI05 is furthest to the west (closest to earthquake area) and shows most uplift.
GPS data (North/East/verstical displacement) by IGN; station HI05 is furthest to the west (closest to earthquake area) and shows most uplift.
A third, intense pulse of quakes and harmonic tremor started late last night and is going on at the moment. A magnitude 3.8 quake early today marks the so far largest event.
The location of the latest quakes moved again a bit further to the west, and is now clustered at about 15-17 km depth beneath the western tip of the island.
If the earthquakes are indeed caused by magma moving opening new cracks and moving at depth, they indicate that pressure has been building up during the calmer intervals and that now magma has continued to migrate and is now below the western rift zone. Interestingly, this is also very near the vent of the (probable) last historic subaerial activity of the volcano, at Volcano de Lomo Negro, in 1793.
The likelihood of the current activity reaching the point to cause an eruption is increasing.
Inflation
GPS measurments from the western part of the island now show a significant inflation (about 2 cm in places), which confirms the interpretation of a new magma intrusion in the area of the quakes.
It will be interesting to see whether the epicenters migrate upwards, in which case an eruption would be imminent.
new earthquake pulse
Update Thu 21 Mar 16:08
Seismic signal from El Hierro today (IGN)
Seismic signal from El Hierro today (IGN)
Map of recent earthquakes at El Hierro (IGN)
Map of recent earthquakes at El Hierro (IGN)
A second, but weaker pulse of earthquakes combined with harmonic tremor started today. The quakes were located in the same area as the last quakes from the first swarm, i.e. at around 17 km depth just north of the western tip of the island below the El Golfo valley. At the moment, it seems that this pulse also is ending.
End of the seismic crisis ?
Update Wed 20 Mar 09:48
Seismic signal from El Hierro 19 Mar (IGN)
Seismic signal from El Hierro 19 Mar (IGN)
Seismic signal from El Hierro today (IGN)
Seismic signal from El Hierro today (IGN)
Activity has dropped progressively during yesterday and has been almost zero today. This probably means that the intrusion (or whatever caused the quakes) has already stopped, and formed just another couple of basaltic dikes deep (16-20 km) under the island.
more than 80 earthquakes so far >magnitude 2, seismic activity decreases
Update Tue 19 Mar 15:09
Map of recent earthquakes at El Hierro (IGN)
Map of recent earthquakes at El Hierro (IGN)
Current tremor signal (IGN)
Current tremor signal (IGN)
So far, there have been more than 80 quakes >M2 and 4 quakes above >M3 today. A clear trend of westward migration is visible, possibly corresponding to magma moving horizontally into new areas. At the moment, the seismic swarm has considerably decreased in energy. Whether this is a pause or already a sign of an end is impossible to say. IF a magmatic intrusion is the cause (there is no proof for this, after all), a plausible scenario could be the build-up of energy while pathways are temporarily blocked. Then, some larger quakes should be expected along with re-appearance of tremor when magma starts moving again.
Update Tue 19 Mar 09:28
Map of recent earthquakes at El Hierro (IGN)
Map of recent earthquakes at El Hierro (IGN)
Current tremor signal (IGN)
Current tremor signal (IGN)
The seismic crisis continues with little changes. A westward lateral migration of epicenters is visible, assumed to correspond to magma movements underground. Depths remain mostly at 15-18 km, with perhaps a slight upwards trend towards shallower areas, but this is not very significant if any. - Volcanic tremor waxes and wanes but remains continuous. - Earthquakes above magnitude 2 today so far (counting only the first 6 hours): 19 / yesterday: ~120 (Note: the total number of quakes including the tiny ones below mag 2 is much higher, but IGN now only counts quakes from a certain magnitude on).
Update Tue 19 Mar 02:31
The total number of earthquakes today so far has exceeded 120, most in the range of magnitude 2-3 and at 16-18 km depth beneath the western El Golfo bay. Volcanic tremor is fluctuating, but still significant, suggesting magma is moving somewhere at depth.
Update Mon 18 Mar 20:53
Map of today's earthquakes at El Hierro
Map of today's earthquakes at El Hierro
The tremor has eased a bit, but quakes continue at high frequency. So far, more than 60 earthquakes have been listed by IGN, mostly around magnitudes 2-3, the largest being one about 2 hours ago with magnitude 3.1 at 18 km depth. The quakes are once again concentrated in the western El Golfo area.
Whether this likely new intrusion of magma is going to lead to another submarine eruption or not, cannot be predicted at this point. It doesn't take much for magma to penetrate the last 15-20 km and rupture the sea floor through a new eruptive fissure, but in many cases, such intrusions remain inside the crust and don't cause an eruption.
New earthquake swarm
Update Mon 18 Mar 18:27
Location of today's quakes at EL Hierro (IGN)
Location of today's quakes at EL Hierro (IGN)
Seismic signal from El Hierro (IGN)
Seismic signal from El Hierro (IGN)
A powerful new earthquake swarm accompanied by volcanic tremor has started under the western part of the island. So far, the quakes are mostly at about 20 km depth. A plausible cause is that another magma intrusion from the mantle into the crust under the island has just started.

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