Taal Update – Ongoing Intrusion

Guest post from Héctor (DustDevil). There will be a further update either later today or tomorrow as events have changed since Héctor wrote this post.

The Main Crater of Taal seems to have calmed down, doesn’t it? However fissures are breaking the ground apart, the river dries, Lake Taal falls and strong earthquakes keep coming. What exactly is going on right now at Taal behind all of these changes?

As I have mentioned a couple of times in the commentary section of the previous post a dyke intrusion seems to be occurring. This is not something you are going to see in the news, at least not the word “dyke”, and at least so far. However, for someone with a particular and deep interest in the workings of rift zones and basaltic volcanoes (like me) what was happening seems obvious.

And don’t let the enormous caldera of Taal fool you, it is a basaltic volcano after all! Might have done a couple of large silicic eruptions in the past with ignimbrites but currently, it has more in common with a shield volcano.

The Macolod Corridor

To understand Taal knowing about the setting is necessary.

Taal is located in the Macolod Corridor, an area varied volcanism, basalts, andesites and dacites are found here. It spans a 60 km long area of southern Luzon, Philippines. Even though small in area there is a number of volcanoes, you find 2 large calderas, Laguna de Bay and Taal plus a number of stratovolcanoes (Banahaw, Makelunyo, Makiling) and monogenetic vents: maars, cones and domes.


If you want to know more things about the setting you can head to this previous article by GeoLurking (and source of the map): https://www.volcanocafe.org/sleeper-fish-a-look-at-the-taal-and-laguna-de-bay-setting/

The secret to the productivity of this region is rifting, you can think of it as a small continental rift. The rifting nature of the Macolod Corridor is well agreed upon, but how this affects Taal and its eruptive history has never really been considered.

A rift volcano

Taal works with dykes, these happen when magma forces open a crack and flows into it, the pressure of the magma and volatiles keeps expanding the crack and so on as long as conditions are right. It turns into a fiery sword slicing through the ground. When it touches the surface, magma comes out though this won’t always happen.

Iceland has an important place in this blog so you are probably already familiar with how important this is in a rift, dykes fill the space opened by the separating tectonic plates.

In Taal it is similar, major events such as the eruptions in 1749 and 1911 included large cracks opening up parallel to the Macolod Corridor and areas of the ground subsiding. This is what concerns most right now because it is what is currently taking place.

The 1749 and 1911 were devastating and if you want to know more about their deadly effects, once again this article by Henrik contains a lot of information on them: http://www.volcanocafe.org/the-tiger-in-the-smoke-taal-the-new-decade-volcano-program-8/

When a volcano intrudes a dyke but it stays deep below the surface, the ground above is pulled apart, it snaps. You get a graben and cracks open which is what happened in 1749, 1911 and now.

Photograph of fractures and subsidence that occurred in a flour mixture when a simulated dike was forcibly widened (dark area, bottom), similar to cracking that occurs at the surface above intruding m

An experiment showing how ground cracking takes place due to the intrusion of magma. The black material at the bottom would represent the dyke. From USGS, Mastin, L.G., and Pollard, D.D., 1988, Surface deformation and shallow dyke intrusion processes at Inyo Craters, Long Valley, California: Journal of Geophysical Research, v. 93, no. B11, pp. 13,221-13,235.

As magma drains away from the magma chamber and into the dyke, the caldera subsides, water flows into the new volume lowering Lake Taal’s water level, it is possible that is the main cause why river Pansipit is currently drying up. However, deformation from the dyke and ash blockage is also to consider which have also been proposed by fellow readers.

Current situation and the future

PHIVOLCS currently maintains Taal at alert level 4 and reports that new cracks keep opening. These seem to be located to the southwest of Taal Lake, coincident with the area of earthquake epicentres. As previously mentioned the earthquake swarm and ground cracking is very likely the result of a dyke intrusion.

The situation plays by the rules of basaltic volcanoes, and don’t get me wrong, rhyolite dykes (and of other magmas) do exist but they are not as frequent. The dyke (usually) starts to intrude under the summit of the volcano, same goes for Taal, this phase involved a subplinian eruption from the Main Crater of Taal and lava fountains on the north flank of volcano island, this happened through the afternoon of January 12, with the lateral vents opening the 13th. Hard to say exactly when (future scientific analysis will have to constrain this) the dyke intrusion propagated to the southwest from the summit to outside the caldera.

PHIVOLCS still warns of a POSSIBLE hazardous eruption. So let’s consider what possible scenarios could lead to another violent eruption:

– Vents open along the dyke: Taal doesn’t seem to erupt outside the Caldera, which is good news to the local population. Bad news is that fissure eruptions are a bit unpredictable and that new or previous vents in the Volcano Island area can open or reactivate, even if unlikely.

– Caldera faults rupture: When magma leaves into a dyke intrusion you drain the magma chamber of a volcano and it can reach the point of collapsing. From a tectonic viewpoint, this happens when the caldera/ring faults give way to the strain they are under, and this is quite sudden! Remember the collapse events of Kilauea? The Talisay (Taal) Caldera is unlikely to undergo major collapse, but the Main Crater in Volcano Island is a smaller caldera structure and more vulnerable.

If this happens we are in uncharted territory but one can picture water making its way to the magma via collapse. Worst case? Probably a VEI 4.

However, it is also likely that dyke intrusion will eventually stop without any these scenarios taking place. The earthquake swarms have slowed down over the last 2 days which could be a sign of the intrusion coming to an end, but since there are ways the situation can escalate again anyone violating the evacuation ordered by PHIVOLCS are putting themselves under grave hazard and in case a paroxysm occurs there is no telling how much time people will have to run, and it may not be enough.

Following Lurking’s advice, do not be there!


294 thoughts on “Taal Update – Ongoing Intrusion

    • All these things you mention make me think of a ” black swan”….could this be that event?

      • Technically no. Not by the criteria established by Taleb.

        However, an argument could be made that Swans are relative in that what is a Swan level event for someone is not that big of a deal for another person.

        In my opinion, Swan like events fall well out beyond 3.5 standard deviations when it comes to probability.

        To recap Taleb’s definition;

        1) So improbable that the likelihood is falsely assumed to be zero.
        2) Profound in their nature.
        3) Logically explained away after the event.

        Item 1 → Shoots the swan idea down. Taal was known to be a major threat and planning (whether good or bad) was made for it.
        Item 2 → Taal fits that pretty well. Just how “profound” is will ultimately be has yet to be determined.
        Item 3 → Self fulfilling. Even this comment falls into that category.

        • If Taal by some very slim chance had a prehistoric style eruption of
          VEI 7 , then in the present day this would be thought to be close to zero chance, if someone asked the question could this go super eruption then the answer most likely would be definitive no . But in reality almost anything is possible. The example of 911, if in say 1975, someone walked into the lobby of one of the twin towers and said on the same day 2 airliners will fly into these buildings and in 2 hours they will collapse on their own footprint leaving not much more than dust, the answer by an “educated individual” would be the chance of 2 planes having having and accident on the same day in the same place is close to zero, the towers were designed to withstand a 707, so collapse that is total is most unlikely, but in hindsight running through how it happened it was obviously not, but could it be expected probably not.

          • Not a black swan, everyone knew before that Taal can go big (and most probably did so in the past). It is still very unlikely that anything bigger than what we know from recorded history happens.

          • The point being if by some chance it did go big then it would be an unexpected event even though in hindsight it was a theoretical possibility thought of before the event, most people would not be expecting it in their lifetime, so in a lot of ways that is a black swan event, same if betelguese went supernova today, no one is really thinking it will do that today even though it couldl

          • This is what leads me to think that maybe a Black Swan could have a relative component.

            Before the megathrust earthquake and tsunami, Kiyoo Mogi raised concerns over the placement of Nuclear power stations with relation to the nearby subduction zone but failed to convince authorities of the issue. (His specific argument was to allow for uncertainties in predictions)

            So, if one guy sees a potential problem, does that negate the Swan criteria?

          • That denial aspect is a big factor if most of the population is in denial of an obvious threat and then it occurs, then to me that seems to fit the definition. An example would be a devastating space rock impact, a known threat, well publicised but most people do not really think it will happen in their lifetime.

          • 9/11 definitely not a black swan, I love probabilities, the chance that the mightiest Military that has ever been, deliberately left their mega populated East Coast with 0 coverage on that particular day and that an airliner found the one tiny area the impenetrable fortress of the pentagon to hit that would cause major damage and that no visible wreckage such as wings would shear off and be visible and that that event would be used to invade Iraq a year later says to this educated individual it was not a black swan.

          • I think you may be on the wrong blog… This is science and volcanoes.. The VC bar can be used for off-topic, within reason.

          • Even though 911 is deliberate, even if it was a bunch of learner pilots recruited from cave in Afghanistan, or part of some more sophisticated plot, nobody believed anyone would be that crazy and evil,it is the belief system that is the important facto what people believe is not possible even if it is.

    • Please check out the green lawn is not covered with ash and the brown leaves trees have roots into it…

  1. I found this map showing old locations for populations in the area, eruptions of Taal have forced many settlements to be relocated:

    It can be seen that the first location of many populations is now underwater. Initially Lake Taal (Bongbong being its original name) was connected to the sea through what now is the course of River Pansipit, but the 1754 eruption filled channel with ash raising the lake level and flooding the villages The eruption was very long, complex and enormous. In a review of historic eruptions it is considered to be a VEI 5 but even suggested to have been a VEI 6.

    The coast between Sala and the first location of Tanauan subsided and was rented by fissures (which continued to the NE) earlier in 1749, It was another rifting event that sadly lacks much information.

    Now isn’t Taal intriguing.

  2. Before (Jan 8)

    and after (yesterday)

    They could do with some rain to wash away the ash

    • If this area is under extension then it would not be unexpected to see the ‘tipped slabs’ like is seen on the greek islands with one steep side rising to the peak, and a long gentle slope on the other side. So what we are seeing isn’t that unexpected if the fault lies in between. Unlike most of the greek islands, though, there is a rich source of magma just underneath.

      • I am not sure where you see the tipped slabs but there are plenty of grabens in the area which would be expected in extension. Particularly the one along River Pansipit, to the sides of the river to normal faults look at each other, in 1911 the central block between the faults dropped, this is taken from https://archive.org/details/jstor-200468

        The same graben seems to have been activated in the last eruption in fact I think that in Agoncillo, which is inside this structure, it has been reported that water from the lake comes farther in than before

    • Taal is not a mantle plume volcano!

      This is not a hotspot/ mantle plume 😉

      Taal is a Subduction – Zone volcano
      Where it gets its magma from a subducting oceanic plate thats pushed down below under indonesia.

      • Ref that subducted plate… it dangles almost straight down in this area.

        • Straight down? Can you link a source, that could mean trench rollback and explain the extension of the Macolod Corridor. Also which is the one diving down, the Eurasia or the Philippine Sea plate?

        • Its evident in the quake plot of the Benioff zone.

          I might drop a plot here tomorrow.

          • That would be great.

            I just learned that the Manila Trench is indeed undergoing rollback at a rate of 3-5 cm/year, eating up the South China Sea.

            That might be creating the extensional forces but there are some questions unanswered, like why only southern Luzon and not the entire island is breaking appart or why is the Macolod corridor is oblique and not parallel to the trench like a backarc basin would presumably be.

          • Probably has to do with the Philippine Mobile belt. I have no clue about its dynamics.

          • This is a slice about 60 km wide running due east and west through the trench and as far as Taal.

            The actual trench curves towards the east near the head of the Palawan micro continent crust that is also involved near Mindoro Island. I did not plot that section.

            The subducted plate in this area is a bit pleated in structure as it desends.

            The “sweet zone” for magma production is about 110 km deep.

            30 year data, USGS source.

          • Amazing that between 120.3 and 120.9 E, which is a distance of about 65 km the slab drops 200 km. I don’t have much of a reference but it looks quite steep.

            I have seen the figure that the Manila Trench retreats at 3 cm/year in the Taal area, the rest of Luzon is probably being dragged by the Manila Trench but the Philippine Trench which is active east of Taal may be keeping the Macolod corridor in place so that it is stretched. If the 3 cm/year all turns out in extension then it is rifting at a considerable rate, faster than the EARS or the MAR.

            The area seems to be both under shear (the Philippine Fault System) and tension (the retresting Manila Trench), and this is probably related to why the Macolod Corridor ends up being oblique.

    • Caroline Plume Is too distant to have any effect at all on Taal

  3. https://www.google.se/amp/s/phys.org/news/2009-07-steppe-mammoths-roamed-southern-spain.amp

    Old but significant news. Arctic Mammoths and reindeer in Sourthenmost Spain during the peak of the LGM. South Spain was long thought as spared from worst effect of the glaciation . But remains of arctic species in southenmost spain, is proof that the tundra extended far south, well below latitude 40 in Europe. The glacial maximum bringed very cold, dry conditions to much of europe.

    During the peak of the Last Glacial Maximum, plants and animals that now live in Spain and Greece, where similar to the plants and animals that today live in Northen Canada.
    LGM also bringed a much much drier climate than today as lots of moisture was locked up in the icesheets

    • Albert: while off-topic its pretty brutal ( Pleistocene cold )
      How was the canary Islands and azores hit by it?

      I expect the Gulf Stream and the wast ocean itself to have milded the Atlantic Islands?
      Protecting them from worst effects of the Glaciation?
      Still Teide coud have had glaciers with todays height back at LGM

      • I don’t know. My guess is that it benefited from the gulf stream. Expect stormy weather..

  4. Does anyone have access/tools/experience to land surface temperatures measurements for the area around #TaalCaldera like this one:


    Does anyone know the source of underground temperature values in common literature? (Ex. 1 km/10 km/30 km?) Is it possible to see different temperatures in seismic data or only different viscosities down to solid state?

  5. Taal SO2 emissions increasing from the last few reports which were ~1440 tons per day. Phivolcs:

    “Latest sulfur dioxide (SO2) emission was measured at an average of 4353 tonnes/day today at 5:00 PM.”

    Normal fluctuation?

    • There is currently an open vent and what appears to be steam possibly is mostly SO2, what seems to be missing here is there a large release of CO2 from the complex as a whole in relation to increased seismic and geological activity across the entire complex?

      • There is no open vent. If it was an open vent Taal wouln´t be inflating. Also don´t forget there was a lake before, most of the visibile steam will be water, not SO2. SO2 is invisible, that´s what makes it dangerous when it collects in depressions around geothermal areas.

        • Guess you have not heard of vog? The gas is visible because of its interaction with the atmosphere and water vapor. This was an eruption of ash and magma at that site, so yes there is some sort of vent at that site, the magma intruding into the caldera is at depth and not necessarily in a position to currently erupt from that vent now or in your lifetime, but not an expert, so sure the experts will chime in and discredit what I said maybe including yourself?

        • A volcano can inflate with an open vent, Kilauea has shown to inflate while having a lava lake at the summit and Pu’u’o’o feeding lava flows, a volcano can hardly be more open than that.

          Also, the inflation is around the dyke intruded to the SW, not in Taal itself. Between the 12th eruption and later dyke intrusion Taal must have lost a substantial amount of pressure which may actually be the cause of all the gas coming out.

      • CO2 increase happened months or years ago, can’t remember exactly. It is usually a very early sign of the supply increasing since CO2 degasses sooner than most other magmatic gases.

    • From the same paper, Lake Taal is mixed with some nasty company in the candidates for large VEI 6 or greater around the world and it is a large list, luckily these things only erupt in tens of thousands of years intervals.

      Found in spam. Sanitized by removing the link. When copy-and-paste a link, it is worthwhile to check what baggage has been added to the link address. It may contain unwanted spies or private keys – admin

      • Ok thanks that table is in the above link for the paper , so no problem.

        • Probably the most dangerous place to be over the next few thousand years is the North island of New Zealand, super volcano central!

          • Earthquake risks may be higher, as there are typically tens of thousand of years separation between supervolcanoes. Wellington might be a good place to avoid.

          • The risk with Wellington is a bit cliche, the biggest risk now identified is the hikurangi trench, now being taken seriously post the 2011 9.0 mag quake in Japan, this area has similar potential, but back to the volcano aspect, the taupe volcanic zone is a relatively small area containing many large Caldera ,last active being taupo only 1900 years ago others such as rotorua tens óf thousands of years, okataina of course had the large basalt eruption of Tarawera -134 years ago, this factor plus being prone to large earthquakes would be a leading candidate for this type of event. Wellingto earthquake although devastating would be recovered from, a massive taupe volcanic zone eruption would destroy New Zealnd as a nation.

          • Okataina enjoys doing VEI 6 eruptions a few centuries/thousands of years appart.

          • In the far distant (we hope) future the one place that strikes me (having recently traveled over part of it) is the american south west. Its clearly had thousands of feet of uplift (see Colorado canyon for evidence) over a huge region and sits just south of major igneous provinces. Other than the odd volcanoes near flagstaff there doesn’t seem to be much activity and admittedly not much earthquake activity either. Likely it will just come to nothing but still, its scary.

      • And I think they underestimate the frequency of VEI 7 eruptions: these seem to happen perhaps 3 times per millennium. But they overestimate the climate impact. There is no real evidence that Rinjani caused the ‘little’ ice age. For one thing, it was too early. These eruptions cause a decade of cooling but have no permanent impact on the climate. Of course the climate may already have been poised for a downturn, in which case a bad event can trigger the cooling. But in those cases the cooling would have happened anyway.

    • I’d put Lazufre complex up on that list.
      Corbetti caldera I think is one of the more worrying candidates for a low end VEI 7 and is one of the fastest uplifting complexes, and you all know about my recent affair with Chiles-Cerro Negro but there is always the chance that the next VEI 7 might happen with an volcano that is overlooked or not even recognized as a volcano.

      • Two of them are extinct, one is no longer capable of large eruptions (Colli Albani) and could even be on the verge of extinction too. Italy was a very different and dangerous place only a few hundred thousand years ago, but now only a few caldera lakes remain to remember that period.

        Only Campi Flegrei seems a credible candidate, but is well monitored and there are no signs of imminent large eruptions, although it is showing increasing unrest in recent years and it is definitely the most troubling among Campanian volcanoes.

    • There’s too much emphasis on the “E” in VEI in my opinion.

      By only including the potentially explosive scenarios, the VEI discounts the potentially even larger atmospheric impacts of relatively non-explosive basaltic eruptions.

      There should be something like a VEVI “Volcanic Eruption Volume Index” that would be more inclusive.

      • Do not worry, Shishaldin is a basaltic stratovolcano, its style consists more of lava lakes, strombolian and lava fountains.

        • It was a joke, but hey maybe Mt Mazama looked like that before it became crater lake!

          • I’m thinking, Mazama would have looked more like Shasta

          • I guess from this angle Shasta looks a lot like shishaldin?

  6. 7 days all magnitudes. New Manila Trench activity today. Near the 1924 6.7 location

Comments are closed.