This is a short update on the activity in El Hierro volcano.
In the last 24 hours there have been no major changes in the activity of El Hierro volcano. No eruption has started yet. But earthquake activity continues with the same rate as in past few days. Magnitude of the earthquakes that are currently taking place is around ML1.5 to ML3.5, with the focal depth of around 20 km. But deepest earthquakes have the depth of around 28 km. While the shallowest earthquakes have the depth around 15 to 12 km. No harmonic tremor is currently taking place in El Hierro volcano. According to GPS data from El Hierro volcano. There is inflation taking place at the current moment. That means magma is injecting it self into the volcano at the depth of 20 km. There is already older magma from last year magma injection. Some of that magma erupted last year, but not nearly all of it. I do not know what happens if the new magma gets into contact with older magma that is in El Hierro volcano. There is also possibility that older magma from eruptions that took place thousands years ago is still in El Hierro volcano. That magma might be andesitic to rhyolitic in nature. If that is the case is impossible to know for sure. But this is always an risk with any volcano, regardless where they are located in the world.
Earthquake activity in El Hierro volcano during last four days. Copyright of this image belongs to IGN.
Earthquake activity during one week in El Hierro volcano. This map clearly shows the extent of the magma during this past week. Copyright of this image belongs to IGN.
Earthquake activity since 1. January 2012 in El Hierro volcano. Copyright of this image belongs to IGN.
Total amount of earthquakes in El Hierro volcano since activity started last year. Copyright of this image belongs to IGN.
Current earthquake activity in El Hierro volcano. No harmonic tremor is currently being detected in El Hierro volcano. Copyright of this image belongs to IGN.
It is difficult to day what happens next in El Hierro volcano. But I do believe that current earthquake activity is going to continue for the next few days to weeks. That activity depends on how much magma flows into El Hierro volcano. That flow might not be constant all the time. So there is going to be period of time with low activity during current events. When this is written, total of around 130 earthquakes have taken place in El Hierro volcano today (29. June 2012) so far.
Known eruptions in El Hierro volcano
Year 4790 BC (Radiocarbon)
Year 950 BC (+- 150 years)
Year 550 BC (+- 75 years)
Year 1677 (Uncertain eruption. Not confirmed.)
Year 1692 (Uncertain eruption. Not confirmed.)
Year 1793 May to 1793 June. Erupted on NW rift, GVP says that the eruption may have taken place at Volcán de Lomo Negro (?). But that is not confirmed or established at current time.
Year 2011 September to December, off the coast. Not on GVP web page.
Source: GVP web page, Hierro
Blog post updated at 20:16 UTC on 29.06.2012.
Hmm, wonder whats going to happen next?
If you want to KNOW, just wait and see.
If you want to GUESS, just shoot your own version to the sky…
A 4.4 quake has just hit El Hierro some 45 minutes ago
That is large compared with normal quakes concerning magma progress.
Can anyone explain this larger quake?
I believe that an rift is forming. That means breaking the crust. That creates earthquakes while it is going on. As the crust there seems to be hard to break for the magma at current depth.
This might take a while and create a lot of earthquake while it is taking place.
I realise this is perhaps not up to your standards but if anyone is interested I have been keeping a running post with list of quakes, seismograms and a YT video of the sequence.
http://quakewatch.wordpress.com/2012/06/27/new-ongoing-swarm-at-el-hierro/
News from Pevolca:
http://www.gobcan.es/noticias/index.jsp?module=1&page=nota.htm&id=149757
“El Grupo de Trabajo, en el que han participado científicos del IGN, CSIC y la Universidad de La Laguna, ha concluido que son esperables terremotos de mayor magnitud en la próxima semana.”
“The Working Group, which involved scientists from IGN, CSIC and University of La Laguna, has concluded that they are expected earthquakes of greater magnitude in the next week.”