Lurking in Plain Sight – Apoyeque, NDVP #2

The location of the Nicaraguan capital Managua is a volcanic one, active and highly explosive even if the past five centuries have been relatively quiet.

The location of the Nicaraguan capital Managua is a volcanic one, active and highly explosive even if the past five centuries have been relatively quiet.

Few cities around the world can claim a more beautiful setting than Managua (pop 2.223 million, 2012), Nicaragua, on the shores of tranquil Lago Xolotlán, Lake Managua. When the Conquistadores arrived, Masaya volcano 20 km from today’s Managua was in eruption and provided Europeans with their fist view of a lava lake. In a letter addressed to the Spanish Emperor Carlos V dated 10th April 1525, the Governor Pedrarias Davila of Castilla de Oro (Panamá) mentions the presence of Masaya and Momotombo volcanoes:

“In this province of Masaya there is a large mouth of fire which never ceases to burn and during the night it is so big as if it reaches the sky, and with a height of 15 leagues (75km) there is light as if it was day.”

The central complex of Masaya. The caldera formed as recently as just over 2,000 years ago inside an older and larger caldera, the 30 kA Las Nubes caldera, which formed following the eruption of a major ignimbrite that can be seen in the Managua area.

The central complex of Masaya. The caldera formed as recently as just over 2,000 years ago inside an older and larger caldera, the 30 kA Las Nubes caldera, which formed following the eruption of a major ignimbrite that can be seen in the Managua area.

Although an – ahem – slight exaggeration, it still gives us an idea how impressive the phenomenon must have been to the Conquistadores. Because of its resemblance to molten metal, it was speculated that it was in fact a pot of liquid gold or silver, and how to extract this vast reservoir of riches immediately occupied Spanish attentions when they were not concerned with theological attempts to classify the phenomenon. From the beginning of Nicaragua’s conquest, the Spaniards referred to the Masaya Volcano as “The Mouth of Hell” or simply “Masaya’s Hell” (“Infierno de Masaya”) with one brave soul; Mercedarian Fray Francisco de Bobadilla, climbing the volcano in 1529 to erect a cross with which to exorcise the “The Mouth of Hell”.

Masaya is classified as a complex volcano but is in reality a shield volcano caldera formed about 2.5 kA BP by a large, 8-km³ basaltic ignimbrite eruption that resulted in the formation of the 6 x 11 km caldera. The phreato-plinian Masaya Tuff has been identified as a 10-20 cm thick layer on the western side of Managua, opposite the Masaya caldera. It has been identified as the result of a wet pyroclastic surge that travelled 35 km from its source (Pérez and Freundt, 2006). After this eruption, a new basaltic complex has grown inside the caldera which includes Masaya and Nindiri cones with the latter the host of the Santiago, Nindiri, San Pedro and, confusingly, Masaya craters.

The 1,297m high Momotombo stratovolcano, here seen from across Lake Managua or Lago Xolotlán, is less than 5,000 years old. (Uncredited image)

The 1,297m high Momotombo stratovolcano, here seen from across Lake Managua or Lago Xolotlán, is less than 5,000 years old. (Uncredited image)

Across Lago Xolotlán and some 45-50 km NW of Managua lies the Momotombo volcano and Volcanic Field with Volcán Cerro Negro, Central America’s youngest (April 1850) and one of the most active volcanoes in Nicaragua almost immediately to its WNW. Momotombo volcano is one of Nicaragua’s most familiar landmarks. It is a somma volcano, meaning it has grown on the edge of the caldera of a mainly collapsed, previous edifice; Monte Galán. It began growing about 4.5 kA BP at the SE end of the Marrabios Range and the symmetrical cone has now attained a height a.s.l. of 1,297 m with a prominence in excess of 1,100 m. If we only take into account the portion above the 400-m isoline, the edifice has a volume on the order of 3.5 km3. In addition to this, there are the products of the geothermal volcanic field on the ESE flank as well as lava flows from Momotombo that have flowed down the NW flank into the 4-km-wide Monte Galán caldera to consider. Also, it has formed a 391-m-high island; Isla Momotombito, offshore in Lake Managua. In all, the volcanic products of Momotombo over the past 4½ millennia is in excess of five cubic km. Consequently, Momotombo has a long record of mainly strombolian eruptions punctuated by occasional larger explosive activity with at least fifteen eruptions since the arrival of the Conquistadores. The most recent in 1905 produced a lava flow that travelled from the summit to the lower NE base of the volcano.

There are two facts to keep in mind concerning Momotombo. First, volcanism seems to be migrating in the direction of Managua; from Monte Galán via Momotombo and into Lago Xolotlán, which is a cause for grave concern in the case of a large-ish, submarine eruption. Second, the copious amounts of juvenile magma fed into and mixing with the crust to form the andesitic lavas. At the very minimum, the rate is in excess of a cubic km per thousand years.

Looking at the map, there are further areas of major volcanism in the vicinity of Managua. Apart from the already mentioned Masaya Caldera and Momotombo, there’s the 6 x 7 km wide Apoyo caldera (Laguna de Apoyo) about 10 km SE of the Masaya Caldera and 30 km from Managua, the collapse of which has been assigned a radiocarbon date of 23 kA BP. Volcanism at Apoyo began about 90 kA BP and the caldera was formed by two plinian eruptions that produced the Upper and Lower Apoyo tephras separated in time by about 100 to a few hundred years. Much closer to the Nicaraguan capital, to the NW and across a bay of Lago Xolotlán, lies the Reserva Natural Península de Chiltepe with the twin, 2½ km crater lakes or calderas Apoyeque and (Laguna de) Xiloá. In the GVP, it is listed as Apoyeke.

Chiltepe Peninsula with Managua city to the right.

Chiltepe Peninsula with Managua city to the right.

Located on the Chiltepe Peninsula, Apoyeque is part of the Chiltepe pyroclastic shield volcano, one of three large ignimbrite shields on the Nicaraguan Volcanic Front. As volcanoes go, it is rather unimpressive as in spite of a base diameter in excess of 10 km, the Apoyeque crater walls do not even attain 400 m a.s.l. with the highest point , “Volcán Chiltépe” – a lava dome on its eastern edge, almost reaching 500 m a.s.l. In fact, it is somewhat reminiscent of Taal minus much of the caldera lake. The summit crater or caldera is 2.8-km wide and 400 m deep, the floor of the lake-filled caldera lies near sea level. Immediately to the SE of Apoyeque lies the 2½ x 3 km lake-filled maar crater Xiloá. On the surface, it is a beautiful setting for recreation for the citizens of Managua, but once you take a look at the history of activity, a very disturbing picture emerges, especially given its location so close to the Nicaraguan capital.

The Nejapa Volcanic Field

The Chiltepe complex and Nejapa Volcanic Field with the locations of some of the major eruptions marked (based on INETER map).

The Chiltepe complex and Nejapa Volcanic Field with the locations of some of the major eruptions marked (based on INETER map).

From the Xiloá crater and through the western part of Managua City runs the Nejapa-Miraflores fault, along the eastern edge of the Managua Graben between the Mateare and Nejapa-Miraflores fault. It is a volcanic field in its own right – the Nejapa Volcanic Field (NVF). It consists of at least 30 volcanic structures of which at least 21 are vents, many of which are maars; phreatomagmatically formed explosion craters and lies almost entirely inside Managua City. Stratigraphy aided by radiocarbon dating suggests that 23 eruptions have occurred in the area during the past ~ 34,000 years with repose times of between 400 to 7,000 years.

The second largest crater of the NVF is the 1.9 km diameter Refinaderia crater, formed about 9.38 kA BP and host to the Managua refinery which has given it its name. Stratigraphy suggests that it was formed by two series of phreatomagmatic pulses accompanied by pyroclastic base surges with a short period of scoria eruption (Strombolian) in between. The second most recent eruption of the NVF occurred at 1,245 (+125/−120) years BP and is the source of the Asososca Tephra. The phreatomagmatic eruptions resulted in the 0.9 x 1.3 km Asososca maar, today one of the main sources of drinking water for the citizens of Managua.

The largest and youngest crater of the NVF is the 1.4 x 2.5 km Nejapa Maar. The associated Nejapa Tephra with a minimum volume of 0.09 km3 covers at least 10 square kilometres inside W/NW Managua City. Again, the erupting magma interacted with water and there are indications of base surges. Radiocabon dating of underlying and overlying paleosoils give an age bracket of 1,200 to 600 years BP for this eruption (Rauch & Schmincke, 2010). The size of the explosion craters in the NVF indicates that the typical maar-forming eruptions are VEI 3 in size with the greatest probably attaining VEI 4.

Chiltepe – Apoyeque

The 300 m high Apoyeke stratovolcano rises to the West beyond the Lago Xiloá maar crater in the foreground. (Uncredited image)

The 300 m high Apoyeque stratovolcano rises to the Northwest beyond the Lago Xiloá maar crater in the foreground. (Uncredited image)

Apart from some recent earthquake activity, the Chiltépe Peninsula has been quiescent throughout the past five hundred years of recorded history. But over the past 17,000 years, there have been at least six major Plinian eruptions from four vents including the two from the Apoyeque and Xiloá vents respectively. If two previous eruptions where neither age nor source have yet been identified are included, the on-shore deposits over the past 60 kA total in excess of 37 km3. This is a summary of the six most recent, major eruptions (Kutterolf et. al. 2007):

  •  ~17 kA BP. Apoyeque, the Lower Apoyeque Pumice, rhyodacite
  • 12.4 kA BP. Upper Apoyeque Pumice, rhyodacite. Ash distribution calculations pinpoint the source to the western end of the bay separating the Chiltépe Peninsula from Managua, the submarine San Carlos crater. The researchers have retained the name UAP though
  • 6.1 kA BP. Xiloá A,B and C, dacite, VEI 5
  • 3-6 kA BP. Mateare, Dacite to Andesite (GVP: 2550 BCE ± 1500 years) VEI 5
  • 2-4.1 kA BP. Xiloa(?), Los Cedros Tephra, dacite (1050 BCE ± 1000 years GVP) VEI 4
  • <2.1 kA BP. Apoyeque, the Chiltépe Tephra, dacite, VEI 6 Initially phreatomagmatic followed by plinian then surge deposits and finally phreatic as the eruption died down. Eruption column height estimated at 35-40 km, slightly greater than the 1991 Pinatubo eruption.

Of these, the Mateare eruption was the subject of a study published in 2005 (Freundt et al). Through density maps of the fallout deposits, they locate the vent to the western side of the Chiltepe Peninsula in the city of Mateare. At the time of the eruption, the surface of Lago Xolotlán was between four and nine metres higher than today which implies that the vent probably was underwater.

Initially, the eruption was unsteady as outside water entered the vent which resulted in great phreatic or phreatomagmatic explosions. The Mateare A layer associated with this phase of the eruption is up to 30 cm thick but has been eroded in many places and mixed or overlain with “Mateare and Xiloá Sands”. These sands on top of the Mateare A layer at one outcrop lies 32 m above the present level of the lake and represents an exceptionally strong tsunami 23-28 m in height. From the location of the Mateare vent on the opposite side of the Chiltepe Peninsula, this wave would have reached the location of present-day Managua City within 15 minutes of the first, large explosion. This initial tsunami was followed by several more but not as great ones. After the initial stage, the eruption became Plinian and deposited the up to two metres thick Mateare B layer. Then as the source of dacitic magma was exhausted the eruption changed and more andesitic magma was erupted to produce the 20 cm thick Mateare C pumice and Mateare D ash and lapilli layers. (Freundt et al 2005)


With the Nejapa-Miraflores fault which marks the eastern boundary of the Managua Graben running all the way to the twin craters Apoyeque and Xiloá, there is a case to be made for the latter marking the Northern end of the Nejapa Volcanic Field. If we accept this, the NVF is shown to be capable of highly explosive dacitic to rhyodacitic eruptions ranging from VEI 4 and up to VEI 6 with less than a thousand years between over the past 6-7 thousand years. If compared with the preceding period up to about 17 kA BP, it would seem that the interval between larger eruptions has decreased significantly with the most powerful eruption <2.1 kA BP.

In most of these eruptions, including the final one at Masaya 2.1 kA BP, water plays a major part which results not only in pyroclastic base surges but also a very great risk of devastating tsunamis. Should a repeat of the Mateare eruption occur on the Eastern side of the Chiltepe Peninsula today, the danger of a major tsunami striking Managua City and its 2.223 million inhabitants within minutes of the first, great explosions is overwhelming. Even a repeat of the Nejapa eruption could be catastrophic on a scale never seen before. The greatest danger of course comes from the pyroclastic base surges travelling through densely populated areas to the city centre a scant 5 km away. However, many of the (residential) buildings in Managua are of such a standard that even 2 cm of ash poses a serious risk of roof collapse. The Nejapa eruption deposited such a blanket up to at least five km from the vent.

Earthquake swarms such as this one in April 2014 at Momotombo stratovolcano and the Chiltepe complex clearly show the area to be very active. (INETER)

Earthquake swarms such as this one in April 2014 at Momotombo stratovolcano and the Chiltepe complex clearly show the area to be very active. (INETER)

In addition to the dangers posed by the Apoyeque-Xiloá complex and Nejapa Volcanic Field, the Momotombo volcano must be considered too. Highly active over the past 5,000 years and with a magma supply of >1 km3 per millennium, the trend shown by recent earthquakes; that volcanic activity may be migrating into Lago Xolotlán where there already has been a major eruption that formed Isla Momotombito, must be considered and closely monitored. And if this isn’t enough, Masaya is another potential MDE volcanic system and there are indications that the magma system of the older Apoyo Caldera is still more or less intact even if it at present is dormant.

Finally, I would like to give my thanks to Dr Hans-Ulrich Schmincke for making his and his fellow researchers’ work available online. It is as exemplary as laudable.



Armin Freundt, Steffen Kutterolf, Heidi Wehrmann, Hans-Ulrich Schmincke, Wilfried Strauch ”Eruption of the dacite to andesite zoned Mateare Tephra, and associated tsunamis in Lake Managua, Nicaragua”, 2005

Kutterolf, Freundt, Pérez, Wehrmann, Schmincke, “Late Pleistocene to Holocene temporal succession and magnitudes of highly-explosive volcanic eruptions in west-central Nicaragua” 2007.
Pardo N, Avellan D R, Macias J L, Scolamacchia T, Rodriguez D, 2008. The ~1245 yr BP Asososca maar: new advances on recent volcanic stratigraphy of Managua (Nicaragua) and hazard implications. J Volc Geotherm Res, 176: 493-512
Rauch, Schmincke, “Nejapa Tephra: The youngest (c. 1 ka BP) highly explosive hydroclastic eruption in western Managua (Nicaragua)” J Volc Geotherm Res, 2010

68 thoughts on “Lurking in Plain Sight – Apoyeque, NDVP #2

  1. Apologies for the delay! Unfortunately, we’ve been hit hard lately with Carl being hospitalised with pneumonia in August (get well soon!) and myself having major surgery three weeks ago. Although I’ve been home a week, I’m not exactly in the pink.

    Apology #2. Seems I have a propensity for spelling Apoyeque “Apoyeke”. I have corrected this in the headline and text but the images still carry the incorrect spelling. 😮

    • All the best for you and Carl! Thank you for a wonderful piece ( again)

      • It was actually Albert who dug it out. All I did was write the piece. Thanks Albert!

        • Central America has had among the highest number of VEI7 eruptions compared to its size in the world. And of all the major cities in the area, Managua seems most at risk. Managua has been hit by a VEI5/6 eruption every 2000 years or so. And the last one was 2000 years ago.

          One report ( recommended relocating the city!

          The Chiltepe area is not normally included in the list of dangerous volcanoes. Most attention goes to Masaya which is always active. Chiltepe seems to do only large eruptions, M4 or larger, with a repose time which is longer than the length of recorded history in the region. Because of the 2000 year repose time it seems benign and is ignored. In reality it is biding its time. Quiet does not mean extinct.

          • Out of curiosity , how does the situation of Guatemala city compare to Managua, it seems the settings are quite similar.

          • Yes, that is also a city with volcanic problems which could have been in the list of ten. But when we looked at specifics, Managua seemed much more at imminent risk than Guatemala City, and this risk seemed not at all well recognized.

          • Cabrageo, as Albert says, we did take a look at the Amatitlán Caldera / Pacaya and indeed Guatemala City/Mixco does lie uncomfortably close at about 40 km. Managua however incorporates the highly explosive Nejapa Volcanic Field and if you look at the map, there’s even a 700 x 800 m diameter maar crater, Laguna de Tiscapa, 1100 metres from the “Metrocentre” (>10 kA BP). Add to that Apoyeque which is so eerily reminiscent of Taal a mere 14 km away “as the crow flies” (Manilla lies ~55 km from Taal) and you get a recent record of at least one VEI 4-6 eruption every 1,000 years with the added danger of a huge tsunami. And we did not even mention the possibility of a flank collapse of Momotombo volcano and the even more devastating tsunami that may cause.

          • Thanks for the replies, google earth geomorphology seems to bear out your assessment, Guatemala city is offset from the main volcanic lineament, Managua sits right on top of it. That Tiscapa maar crater looks like it sits on yet another faultline. Would these maars be associated with water percolating down the faults interacting with the magma system at depth then? Definitely would add an element of unpredictability.

        • They seem to be. Whereas almost everywhere else (with the possible exception of Campi Flegrei, Rabaul and a few other places), the record goes back at least 250 – 500 kA, there were only a few references to volcanism in the 30 – 90 kA age bracket. It is as if someone has applied a giant eraser to anything older and that eraser is more recent volcanism. Most of what can be unravelled seems to have taken place during the past ~20 kA.

          But please, do read the papers linked to in the article! They are highly informative even if so much on the technical side that you have to deduce the implications for yourself.

    • Another good article. It’s so beautiful there, but so deadly.

      I hope you and Carl will be up to par soon. It takes a while to recuperate from both things.

  2. Excellent post, my old geology prof spent time in Managua. He would agree that here is indeed a problem….

  3. A very interesting post – thank you! I wish you a swift return to full health, Henrik, and Carl, I hope you are over your pneumonia soon. Perhaps you are overdoing things? (And stay away from ashy volcanoes!)

  4. Another thing worth mentioning is that this is a very seismically active, and dangerous region in addition to being a big risk for Volcanic activity. Managua is one of those cities that look like a great location on paper until you look into the natural disaster risk factors. It may take a long time, but this city has an expiration date as morbid as that may sound. Compound that with a low level of mitigation, and you get #2 in the DVP.

    Apoyeque is an interesting volcano. I suspect that the graben (which is also an active back-arc basin) is similar to a young Kagoshima Graben. I’ve said this in multiple posts over the years, but areas of thin crust (or rifting) in active subduction zones will provide you heightened volcanic activity. I don’t know if there is a slab gap from the subducting slab breaking off, but wouldn’t be entirely surprised if this was beginning to take place in this region. The style of volcanism here reflects that type of activity, with heightened basaltic activity, along with heavy bimodal volcanism.

  5. Thanks Henrik & Albert for the nice informative article.
    Even a smaller event near or in (!) Managua would cause very nasty things …
    Some of those cataclismic ‘Volcano and/or Earthquake cataclism’ catagory films could become realistic in a city situated as Managua. Terrible if so.

    Dyngjuhals plot from IMO, looks quite a rumble, IMO did give a 2,6 only at 00:36.

    • Must have been close to the sensor and also, it must have had a sensitive setting. Have you compared to other nearby stations?

      • Ah ja, thanks Henrik, just after midnight. Reset of measurement sensivity takes place at that point every day as I read earlier.
        Here is another. The first one smaller reading in graphic at 21:02 M1,5 and the larger reading in graphic just after midnight M1,3.
        It shows the sensitive setting after midnight (but nevertheless, dyn registers quite pronounced comparing to the surrounding stations is my feeling…).

        Thursday 08.10.2015 00:04:51 64.619 -17.446 1.1 km 1.3 90.02 4.6 km ESE of Bárðarbunga
        Wednesday 07.10.2015 21:02:35 64.668 -17.425 0.5 km 1.5 89.59 5.8 km ENE of Bárðarbunga

        Source: IMO

        • Beautiful illustration Rob! And with the more sensitive setting, several minor quakes appear in the hours just after midnight which gives the false impression of a sudden increase in low-level activity. The traps are many and varied!

        • Just for the record, the review.
          Thursday 08.10.2015 00:04:51 64.620 -17.450 8.5 km 2.0 99.0 4.3 km ESE of Bárðarbunga
          Wednesday07.10.2015 21:02:35 64.674 -17.457 8.1 km 1.7 99.0 5.0 km NE of Bárðarbunga

    • Managua is the second largest city after Guatemala City.

      The city was hampered by major floods in 1876 and 1885. A disastrous earthquake in 1931 and large fire in 1936 destroyed much of the city. It suffered a second major earthquake on December 23, 1972, which destroyed 90% of the city’s downtown and killed more than 19,120 people! (

      Last year we spent some time in Masaya not to far from Managua. There we met a doctor who happened to be in Managua when the second big earthquake hit. He was so traumatized he refuses to go there any more for shopping (It is believed that another quake is overdue). This was an interesting response since at midday on July 6, 2000 an earthquake whose epicenter was located in the volcanic lake known as Apoyo, just 6 km from the city of Masaya, registered 5.9 on the Richter scale.( There was still plenty of damage visible in Masaya when we were there. Regarding Masaya, a quote in the above article probably answers you question. “Masaya Trembles: The Lessons of a Disaster: Nicaragua’s most densely populated area is riddled with fault lines. Recent earthquakes in Masaya offer us more lessons on how to reduce the dangers of living there, but nobody seems to want to learn. Should we all just move to the Caribbean coast?” Regarding your question about Manaugua, I doubt it is much different in terms of preventive measures, based on discussions with the doctor.

      While in Masaya, we visited the Masaya volcano. It is constantly giving off gases including loads of SO2 and probably some HF. These vapours make viewing the bottom of the crater difficult depending on the direction of the wind. The vapours were so acidic an old metal barrier dissolved and was replaced by a wooden one. The doctor was very concerned about the guides who are constantly exposed to this gas. At night we traveled with him to the other side of the crater. From a rickety, corroded platform with no guard rails we could look down into the very deep, narrow, cylindrical part of the crater. I held onto my wife very tightly. Occasionally. you could see a pinkish glow of the lava at the bottom. Masaya is known as the center of the rebellion against the dictator Somosa. They have a great fete once a week in an old fort in the town. There you will see foklorica put on by local people including patriotic songs about Masaya and the revolution.

      We also stayed at the bottom of Apoyo crater which has a very deep lake temperature of 35 + degrees C. It has fish in it and great swimming. Swimming is a bit scary as the lake is in the form of an inverted cone and a few meters from shore one is swimming over an abyss. I would get up early in the morning and walk a dirt track along the lake to see wild life including howler monkeys. A great place to visit if sleeping in a very active volcanic area does not bother you. There is a great guest house there run by some young French people.

    • All within the hydrothermal zone (0 – 3.5 km depth) and of a size consonant with hydrothermal (or minor tectonic) activity. 🙂

      PS. There were only thirteen (13) earthquakes on the 7th. The complete list goes a full year back to October 12th last year.

  6. Great post, Henrik and Albert. Can’t wait for #1.

    Out of learning/curiosity I’ve been following the “Sheldon” situation where there seems to be magma movement in a place where there hasn’t been a volcano in the past. It’s been going on for about 16 months. One of the reasons that this is interesting is that there is so much data available. here:

    and discussions here:

    I realize that this has been posted before (thanks KarenZ), but it seems to keeps getting stronger.

    Don’t think this will ever make the MDE list, but the 10 antelope within 40 km might need to evacuate.

    • Yep, but Lakeview would have a real tourist draw.
      they even have a fairly decent airport…
      That said, I think we are looking a magma movement.
      Several hot springs around, and there are a few old sills
      and exposed dikes in the area. Also cinder cones of various
      sizes and ages..

  7. Hello, form (finally! ) rainy NE Oregon. here is a bit from the Washington Post on the Siberian Traps vs. the Permian Extiction:

  8. Some time ago, one of our readers, Mr Albert Figaro, sent us this lovely picture of Cotopaxi taken on September 12th:

    • so, we’re having a contest on the most beautiful volcano picture, Huh? I’m voting for Popocatepetl:

  9. Yesterday, Aso had another hiccup according to Mike Ross who posted this webcam capture on Facebook.

    • Why are so many Japanese car park security camera pointing at a nearby volcano? I guess volcanoes must the main cause of damage to parked cars, Japan in the main having a reputation as a very safe country.!

      • That’s just a normal average volcano webcam – it’s on the roof of the Aso volcano museum. Next time I’m there I’ll take a pic of it from the other side 🙂 – nothing to do with car park or security.

        PS thanks for grabbing it Henrik; I’d have posted it here myself except… well how DO you post an attachment?!

        • I use copy, paste, upload, paste the bbb link to your comment and remove the stuff in the brackets.

      • Gennerally, if the link is a bona-fide image and ends in a jpg or gif extention and has no superfluous scripting markup, the blog software will embed the correct coding to make it an inline image.

        To do otherwise is inviting trouble. That’s why embeds to java and ActiveX encapsulated images don’t work. Though Java is supposed to be a sandbox environment, there are ways that an adept script author can break out of the sandbox with their script. (a MAJOR problem with ActiveX. ActiveX is a hacker’s dream come true.) Breaking out of the sandbox essentially gives the script full access to your machine.

        NOTE:My statement about ActiveX is my opinion and does not represent the view or opinons of VolcanoCafe or it’s other moderators/operators.

        If you wish to research this in greater depth, I recommend:

        Some of Java’s problems:

        And ActiveX’s issues:

          • Mike, I cheated and used my admin powers. After some slight editing, I uploaded it to our media library as it could turn out to be handy to have access to this particular image at a later date. As you can see(?), from the name of the jpg-file one can tell where it originally came from. I’m particular about that.

          • Ahhhh ok. So I’m not losing my touch; admins can post pics directly, plebs can’t? That sucks a bit; makes it less convenient to post pics. I’d have posted this one myself – but hot links to FB pics generally don’t work

          • Not so Mike. In order to be able to write articles et.c. there are certain vital and necessary tools available including a “media gallery”. Like Lurking points out, if everyone had access it wouldn’t be long before there were nasty trojans embedded everywhere. And it’s not like readers cannot post images at all. For future reference, if you have posted an image to FB you can always copy the FB image ID and paste that in a regular post.

          • I found linking to pictures on image hosting sites to be hit and miss. The problem is that it doesn’t tell you why an image is not showing. If you can find the link to just the image itself, without the site advertising script, it should work. I am also not sure where it accepts all formats.

          • In my experience, if the link ends in jpg or gif and has not scripting, WordPress treats it nice and embeds it.

            I tend to use TinyPic and once I have the image in a window by itself, I copy the link to the image from the browser addy and use that.

            The issue with TinyPic is that after some time has passed, the image goes away. That’s how I lost the image to the harmonic looking energy bands in the SISZ. I still haven’t located it on my PC to re-upload it or drop it into the media library…. and I’m not sure I even have that set of quakes in a spreadsheet anywhere.

          • That doesn’t show for me, and trying to open the link in a different window also gives me an error. Perhaps it requires a faceboook account?

          • Hi Mike, tried digging into the source for that – it suggests you’re trying to paste a link to an image that is hosted on

            but that doesn’t actually seem to have an image there

            mostly I upload an image
            then right click the image – copy image url
            and then paste that on a fresh line
            I’ll try it with something from the eruptions blog

  10. Someone can explain the tremorreadings from Slysaalda?
    Also Mjoaskgard, Godabunga and Fedgar are joining.

    Source IMO.

    • You can count Godabunga out as that is always active no matter what goes on elsewhere. However, Slysalda, Fedgar and Mjoskard all lie between Myrdalsjökull and Torfajökull-Hekla in the Vatnafjöll area, so it points to something happening in that area. The signature seems to by hydrological in nature (in my amateur opinion) even if there was a M0.8 (equivalent to the energy content of a cheeseburger) at 9.8 km below Vatnafjöll early this morning. Sudden rise in the level of one or more rivers after a period of rain and storms?

      • Hi, Might be worth keeping an eye on the drum plots for this area. Wished I’d grabbed a screenshot but saw some interesting tremors yesterday on FED but figured it was related to the tectonic quakes nearby, although iat first it was magmatic.

        Anyone else see them, I’m not great at spotting harmonic signals and would be great to hear what someone else thinks?

      • Godabunga could get interesting if it receives a fresh pulse of magma. That cryptodome has been sitting there a while.

  11. The Katla Area keps going at it. Tho I think the activity might be actually closer to Torfajokull than Katla. Considering the recent unrest in that area, I would not be surprised if it would be around Torfajokull.

    Looking at the SILs, it looks quite quake-ish, kinda like a small swarm.

    And when you look at the drums, that is actually exactly what it is.

    I do not exclude a possibility of a more like a hydro event, or hydro-thermal. At least no immediate magma is involved, since the low frequencies are more silent for now, and no harmonic tremor was detected whatsoever. Should this continue and increase with time, and the lower frequencies would start to emerge with some HT pulses, than that might be a sign for something more ominous.

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