This is Part 60 of the El Hierro Volcano eruption report
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With the collaboration of Joke Volta, an El Hierro resident and Julio del Castillo Vivero, photographer.
Links to earlier parts of this extensive El Hierro eruption report :
(28/7 – early 09) – (25/09 – 10/10) - (11/10 – 13/10)- (14/10 – 17-10) - (18/10 – 21/10) - (22/10 – 26/10 ) - (27/10 – 31/10 ) – (01/11 – 03/11 ) - (04/11 – 06/11 ) – (07/11 – 08/11) – (09/11- 11/11) – (12/11 – 15/11) - (16/11 – 19/11) – (20/11 – 23/11) – (24/11 – 27/11) – (28/11 – 02/12) -(03/12 – 07/12) – (08/12 – 11/12) – (12/12 – 15/12) – (16/12 – 18/12) – (19/12 – 25/12) – (26/12 – 31/12) – (01/01 – 03/01) – (04/01 – 07/01) – (08/01 – 13/01) – (14/01 – 19/01) - (20/01 – 25/01) - (26/01 – 30/01) – (31/01 – 04/02) – (05/02 – 10/02) – (11/02 – 16/02) – (17/02 – 23/02) – (24/02 –29/02) – (1/03 – 10/03) – (11/03 – 18/03) - (19/03 - 23/03) - (24/03 - 28/03) - (29/03 - 03/04) - (04/04 - 10/04) - (11/04 – 21/04) - (22/04 – 30/04) - (01/05 – 10/05) - Part 43 (11/05 – 31/05) - (01/06 – 14/06) - (15/06 – 24/06) - (25/06 – 26/06) – (27/06 – 28/06) – (29/06 – 01/07) - (02/07 – 06/07) – (07/07 – 31/07) - (01/08 – 31/08) - (01/09 – 11/09) - (12/09 – 30/09) - (01/10 – 15/12) - Part 55 (16/12 – 16/03) - Part 56 (16/03 – 26/03) - Part 57 (27/03 - 30/03) - Part 58 (31/03 - 12/08) - Part 59 (13/08 - 30/11) - Part 60 (1/12 - 25/12)
2013-12-25 22:58 UTC
- A very interesting new episode in the current crisis. A calm seismic period but a continued deformation, both vertical and horizontal. In earlier crisis, once the seismic unrest stopped, also the deformation leveled or stagnated. No the lifting continues in most points as the latest IGN GPS stations are showing. All this means that this crisis is not over yet and that new seismicity is evident when the island is pushed upwards. The Upwards deformation data are really spectacular (U side of the graphs) - In only 3 days HI09 (La Restinga) lifted 6 cm! and HI08 (El Pinar) 5 cm. But not only the South-Eastern side of the island was lifted, but also most of the El Golfo area with an average of 4 cm.
2013-12-25 19:51 UTC - For passing by-ers who are looking only at the earthquake list, it looks like everything is over again. We are not convinced that this is the case. We are constantly looking for patterns, mainly because of the strong continuing deformation as reported this morning (by both IGN and Uni of Nagoya). The La Restinga seismograph is almost flat which explains also the only sporadic earthquakes on the IGN list. We keep you updated.
2013-12-25 13:31 UTC - No change in the Update 09:31 UTC situation
2013-12-25 09:31 UTC - Back to the pilot modus? No more listed earthquakes since 03:46 UTC, although we still see some activity and even some tremor on the La Restinga seismograph. - A very dispersed image of depths, ranging from 12 to 19 km (average 14 km) based on the latest listed earthquakes - The weakening can however not be seen on the latest IGN deformation map where La Resinga HI09 (IGN) shows a lifting of another 2 cm (same than the prior 24 hours) and El Pinar also 2 cm up and a push to the North.. If this lifting will continue, this means that the accumulated energy will try to release itself with more earthquakes. Unfortunately, we only have GPS deformation data once a day. - The University og Nagoya / Involcan GPS station is reporting an even stronger lifting to the North of the El Pinar GPS station. Both IGN and Uni of Nagoya are indication that the pressure is building further up below the island. - Also important to mention is that the magma source below the island should be in between La Restinga and El Pinar. Why ? because the NS deformation charts of IGN is showing a thrust to the North in El Pinar and a thrust to the South in La Restinga.
2013-12-25 01:36 UTC - Hard to say whether it is already ended or not. Surely a lot weaker with only very limited seismicity. - IGN has started to list weaker earthquakes again. A M2.1 at 9 km depth was reported at 00:11 UTC.
2013-12-24 16:36 UTC - It took a while before the last interesting (low frequency) earthquakes were listed, but now we see another of these earthquakes at 9 km depth (not dangerous but certainly one that IGN will zoom into). To give our readers an idea of the epicenter of both 9 km depth earthquakes, we generated a map of the epicenter of both quakes. We are unsure about the depth (no good seafloor maps on the internet. Google earth mentions 500 to 600 meter.
2013-12-24 15:20 UTC A typical phenomenon happened only a couple of minutes ago. A seemingly calm and weaker seismic period ends with another strong(er) earthquake (no details yet but we expect in the M3 proximity). How can this be explained : quiet simple - pressure buildup with almost no release of energy which (within an active period) ens with a stronger than usual earthquake. Also this is a low frequency earthquake! (lucky to have explained it in the 14:13 update )
2013-12-24 14:13 UTC We think it should be a good idea to explain to our readers the difference in between the different types of earthquakes, as soo many earthquakes are currently occurring below the island. The (scientific) text was initially written by Tilling, et.al., 1987, Eruptions of Hawaiian Volcanoes, but is also to be used everywhere else in the world.
During inflation (lifting of the island as discussed in previous updates) the rocks become stressed, and this stress is partly relieved by increasing numbers of earthquakes, too small to be felt, but easily recorded by seismometers at Kilauea summit. These earthquakes (called short-period or tectonic) are recorded as high-frequency features on a seismograph. During deflation the stress is completely relieved. The short-period earthquakes stop, but their place is taken by low-frequency earthquakes (called long-period or volcanic), which reflect adjustments related to the movement of magma from the reservoir to finds its way to the surface. The long-period earthquakes are related to harmonic tremor, the continuous seismic record of underground magma movement. (small adjustments to the text to reflect the El Hierro event).
2013-12-24 12:49 UTC - New stronger earthquakes and a thicker tremor line (magma intrusion)
2013-12-24 12:29 UTC - The strength and frequency of the earthquakes has weakened the last couple of hours. Microseismicity is still present abundantly.
2013-12-24 09:50 UTC - Relatively few earthquakes today (less than yesterday) - some information for both ends of readers. Those on the island who merely want to live their safe live and want to enjoy tourist spending : less earthquakes. Those (almost all from other places in the world : it is not over yet. - The seismograph image below shows a strong earthquake at 06:17. If you are looking in the list for this earthquake, you will be surprised that it is only a 2.4 Magnitude. Why such a big line on the graph then? Because of the depth of 9 km. The seismograph is the confirmation that the depth must have been true (in seismology error margins are normal - in preliminary readings). - Some activity is taking place offshore at the east of the island. - Magma wint gradually into a more shallow layer. It went up approx. 2 km (from 15 to 17 km towards 12 to 15 km (last 5 earthquakes). - The seismograph image shows at the end some more tremor indicating a further intrusion of magma. These quakes are not yet showed on the list. - De El Pinar GPS deformation data is showing a Northern deformation of nearly 2 cm. More lifting of a bout 1 cm. - The IGN deformation data are showing a further lifting of 2 cm! on the HI09 (La Restinga) GPS and a 1 cm lifting of the El Pinar HI08 GPS. this means lesser lifting in El Pinar and more lifting in La Restinga than the prior 24 hours. These readings are confirming what we see on the seismicity map. - In terms of safety on the short term, we are convinced that a PEVOLCA will meet soon and will publish a report afterwards. (PEVOLCA safety board of the island consisting of IGN, INVOLCAN and the local and national authorities)
2013-12-24 00:58 UTC - 110 earthquake on Monday - Involcan has reported that the amount of Radon gas has increased. Radon gas exsolves early from the magma, leaks from the magma chamber, and escapes diffusely through the edifice of the volcano and is of course another indication of the current seismic crisis. - The depth of the earthquakes is still about the same, BUT the epicenters of the earthquakes are traveling south and have almost reached La Restinga.
2013-12-23 18:02 UTC - We just had contact with Joke Volta who lives in El Pinar, exactly the area with all the current epicenters. She said that she felt nothing important, just some light shaking now and then. - If we look at the IGN deformation graphs (see below), 4 GPS stations are showing lifting deformations of around 2 cm HI08 is normal of course (the current epicenter area), but Hi09 (La Restinga part of the island), FRON (Frontera) and HI02 (El Golfo) who have almost the same upper deformation. All other stations on the island remain unchanged (please note that HI10, also on the lifting axe, has stopped reporting earlier this year). - 99 earthquakes so far today !
2013-12-23 13:28 UTC - Involcan (Nemesio Perez) and IGN (Carmen Lopez) are saying the same as we have done since the beginning yesterday - 58 earthquakes listed by IGN so far today - Location last earthquakes (El Pinar area) = unchanged - Hypocenter depth : 15 to 18 km = unchanged
2013-12-23 09:32 UTC - If you live in El Pinar, you do want to see the epicenter of the last set of earthquakes below. Almost all the current seismicity is concentrated in the direct El Pinar area (red squares). The initial earthquakes started in the El Golfo area (green squares are the older quakes). But, we repeat, at the current depth there is no immediate risk. If IGN would see any danger, they will act swiftly (we are convinced about that). As stronger earthquakes are expected we would advise people living in El Pinar to read our Be Earthquake Prepared section
2013-12-23 08:49 UTC - Confirmation of the current Magma thrust below the island comes from the deformation data from Involcan - University of Nagoya (Prof. Sagiya) El Pinar GPS station. The thrust has led to an upwards deformation of at least 2 cm (Ultra Rapid data, to be confirmed later). De deformation to the North-East is less than a cm.
2013-12-23 08:00 UTC - The earthquakes are continuing below the island. The 121 earthquakes since yesterday morning is in fact hundreds if we also count the microseismicity (quakes of less then M1.5 which IGN normally list during non-crisis periods - so far not dangerous at all as the magma is locked in the 14 km (average) layer - A new episode from magma on the move has just started now (thicker tremor line). If this continues for multiple hours, the epicenters may move in another direction.
2013-12-22 23:42 UTC - The activity continues, although with less tremor than in the early afternoon. - 63 listed earthquakes (we say listed, because there a a lot more of them). IGN does not list the very small ones anymore once a crisis is starting. They did this at the start in 2011, but in 2012 they changed the type of reporting. - The strength of the magma feed can be seen at the increasing number of earthquakes above 2 since the last hours. We expect more powerful ones during the nightly hours. - Epicenter in the greater El Pinar region
2013-12-22 19:44 UTC Our opinion written during the first update this morning became true, a new magma intrusion is occurring below the island. Some people are so excited about the new activity that they are spreading some kind of minor panic. We emphasise that IGN did a great job in following up all other crisis and that they are standby 24 hours a day. The location were they are watching the instruments (Madrid or El Hierro) is totally unimportant at this moment. The earthquakes are still in average in between 13 and 15 km with NO fast progression to a shallower depth. IGN will increase the number of instruments (some were apparently broken after the bad weather) and will certainly be replaced. We will of course NOT comment on every earthquake BUT we are following up what happens and will report asap when something new and relevant is happening (as you now of course). - The activity as it started this morning is intensifying. Nobody knows what wille happen the next minute, hour, day or week. It can suddenly stop or it can continue.If it continues we expect even stronger earthquakes than the ones so far, this based on earlier crisis. Good to repeat that only earthquakes (below first 10 km and later 5 km) will throw another light on the current situation. - 41 earthquakes so far today - IGN reports 4 felt by the islanders but we think there are more felt, but only 4 reported at IGN. - The epicenters of the last 10 earthquakes are mainly at the eastern part of the island, a totally other section than where earlier activity was noted. This brings a new uncertainty in the field as we do not know the resistance of this part (we know it from other parts). - The intrusion has calmed down since a couple of hours (see the tremor line below getting thinner, but a new strong quake can change everything again - pressure building up until it breaks). Do not hesitate to comment on the bottom of this page if you are among those following this activity from nearby. Remark : A 0 depth earthquake is (by the way) in 99.9% of the cases an instrument error and not a shallow earthquake. - Something relaxing for our friends at the US and South-American East coast : We know that a lot of people are fearing a collapse of the island, but what is happening today occurs at the opposite end of the island.
2013-12-22 15:20 UTC As said in our prior updates a magma intrusion is currently going on below El Hierro. So far the strongest earthquake is a M3.2 at 12:16. Stronger earthquakes may be expected. The depth remains at a safe level.
2013-12-22 10:22 UTC The seismograph screenshot from La Restinga shows the current activity. Apart from the listed earthquakes, we also see a lot of micro-seismicity (mainly by comparing the graphs from the past days). Please note that most of the oscillations are coming from human triggered events (seismographs are very sensitive). The thicker tremor line started however when seismicity increased.
2013-12-22 09:21 UTC A sudden increase of seismicity. Too soon to talk about a new crisis, but with 5 2+ Magnitude earthquakes on 13 quakes, this looks to be more than the usual small -M1 quakes we have seen the recent weeks. (Thank You Leona for alerting us). Stronger earthquakes are within reach today. Most epicenters are located in the El Golfo area and some of them may even have been felt by people living in Frontera. The depth is normal for all beginning activity. As long as the hypocenters (breaking point generating the earthquakes) is not below 10 km, looking for an eruptive episode is not realistic. Shaking from earthquakes is starting to be dangerous from M3 on for landslides (steep cliffs area) and from M4 on for structures (mainly cracks in walls and NOT collapsed houses).
2013-12-21 09:37 UTC Activity below the island has almost arrived at a standstill as we had only very few earthquakes the last week. - We have just archived Part 59 of the El Hierro story (we still believe that a new activity period can appear the following days, weeks, months ...). Link at the bottom of this page.
2013-12-18 18:47 UTC Readers Berry and Leona have told us earlier today that the CHIE graph is alive again. The sensor has however been replaced by the CTIG seismograph. Only 2 earthquakes since our last update on December 14!
2013-12-14 23:14 UTC No more active seismographs working at this time (reason of the bad weather ?). Let's hope IGN will repair them soon.
2013-12-11 11:04 UTC Except for bad weather the last couple of days, with the result of thicker seismograph lines, nothing spectacular happened. Below the list of the limited seismicity.
2013-12-02 13:12 UTC Reader Leona traced the probable reason of the tremor on the CHIE station : torrential rains and a low pressure system which provoked several landslides ! This happens regularly with seismograph stations.
2013-12-02 12:30 UTC Readers Frederick and Leona have seen a change in CHIE. Is there indeed a change in the tremor? The graph shows a thicker line but there is no reason to believe that a new magma flowing period has started below the island. Reason : the tremor has not changed in other (more sensitive) stations and there is no trace of any seismicity neither. But it is surely interesting to follow up, which we will do. The earthquake earlier today was in between Gran Canaria and Africa.
Links to earlier parts of this extensive El Hierro eruption report : (28/7 – early 09) – (25/09 – 10/10) - (11/10 – 13/10)- (14/10 – 17-10) - (18/10 – 21/10) - (22/10 – 26/10 ) - (27/10 – 31/10 ) – (01/11 – 03/11 ) - (04/11 – 06/11 ) – (07/11 – 08/11) – (09/11- 11/11) – (12/11 – 15/11) - (16/11 – 19/11) – (20/11 – 23/11) – (24/11 – 27/11) – (28/11 – 02/12) -(03/12 – 07/12) – (08/12 – 11/12) – (12/12 – 15/12) – (16/12 – 18/12) – (19/12 – 25/12) – (26/12 – 31/12) – (01/01 – 03/01) – (04/01 – 07/01) – (08/01 – 13/01) – (14/01 – 19/01) - (20/01 – 25/01) - (26/01 – 30/01) – (31/01 – 04/02) – (05/02 – 10/02) – (11/02 – 16/02) – (17/02 – 23/02) – (24/02 –29/02) – (1/03 – 10/03) – (11/03 – 18/03) - (19/03 - 23/03) - (24/03 - 28/03) - (29/03 - 03/04) - (04/04 - 10/04) - (11/04 – 21/04) - (22/04 – 30/04) - (01/05 – 10/05) - Part 43 (11/05 – 31/05) - (01/06 – 14/06) - (15/06 – 24/06) - (25/06 – 26/06) – (27/06 – 28/06) – (29/06 – 01/07) - (02/07 – 06/07) – (07/07 – 31/07) - (01/08 – 31/08) - (01/09 – 11/09) - (12/09 – 30/09) - Part 54 (01/10 – 15/12) - Part 55 (16/12 – 16/03) - Part 56 (16/03 – 26/03) - Part 57 (27/03 - 30/03) - Part 58 (31/03 - 12/08) - Part 59 (13/08 - 30/11) - Part 60 (1/12 - 25/12)
Volcano Discussion Panel : If you are a person who wants to discuss and read about all aspects of volcanoes, this discussion panel might be a very good place to hang around. Especially if we start speculating about what to happen next.