In May, 2006, the Lusi Mud Volcano in eastern Java, Indonesia came to life, smothering much of the surrounding land in mud.

According to the article Indonesia's Infamous Mud Volcano Could Outlive All of Us (Normile, 2011), there is considerable uncertainty about what actually triggered the eruption in the first place. The main ideas of what possibly caused the eruption, as reported in the article are:

  • Nearby drilling
  • A relatively nearby 6.3 magnitude earthquake 2 days earlier.

Is there any consensus of what caused the Lusi Mud Volcano eruptions in Indonesia?


2 Answers 2


No, there is no consensus.

In fact, there's quite a bit of debate about it — around the 2 causes you mentioned. To sum up the proposed triggers:

  • The eruption happened about 2 days after the 2006 Yogyakarta earthquake, which killed over 5000 people. Lupi et al (2013), Sawolo et al. (2011), and others including the Indonesian government, favour this as the trigger.
  • The eruption happened about 200 m away from Lapindo Brantas's Banjar Panji 1 exploration well. There were early signs of trouble in the well, which started when the earthquake happened. At the time, the incident was treated as a blow-out, relief wells were drilled, etc. Davies et al. (2011), and others, blame this.

Last year I blogged about Lusi. The first-order cause was not my focus (though I insinuated that I thought the well exploited a predisposition set up by the earthquake); I focused instead on the history of the event. But much of the controversy emerged in the comments, which are worth reading.

Rather than trying to synthesize everything into an elegant summary, I'll just point out two of the complications in all this:

  • The Lupi et al (2013) argument has serious flaws, because the authors misinterpreted the sonic (DT) log from the well. This was partly, but not completely, resolved by the corrigendum published in 2014. In a nutshell, the fast layer they argued for was a logging artifact.
  • There is a legal backdrop to the argument, which may not be compatible with an objective scientific debate. For the company, there is the question of liability and thus reparations, which could be expensive. For the government, there is the question of international financial relief, some of which is contingent on Lusi being a natural disaster.

The debate may not be satisfactorily resolved for some time. It seems to be one of those unhelpful debates where, to the participants at least, there is no uncertainty. My heuristic in such situations is to assume this means that "it's complicated".


  • Davies, R, S Mathias, R Swarbrick and M Tingay (2011). Probabilistic longevity estimate for the LUSI mud volcano, East Java. Journal of the Geological Society 168, 517–523. DOI 10.1144/0016-76492010-129.
  • Lupi, M, EH Saenger, F Fuchs and SA Miller (2013). Lusi mud eruption triggered by geometric focusing of seismic waves. Nature Geoscience 6, 642–646 (2013) DOI 10.1038/ngeo1884.
  • Sawolo, N, E Sutriono, B Istadi, A Darmoyo (2009). The LUSI mud volcano triggering controversy: was it caused by drilling? Marine & Petroleum Geology 26 (9), 1766–1784. DOI 10.1016/j.marpetgeo.2009.04.002.
  • 1
    $\begingroup$ Excellent answer - and thank you for the link to your blog too, the comments are indeed compelling. I will definitely subscribe/keep an eye on the discussion on the blog as well. $\endgroup$
    – user889
    Jan 10, 2015 at 12:36
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    $\begingroup$ Cheers! I'd been meaning to post a follow-up summing up some of the issues in the comments, so I feel inspired to try that again. I'd asked one of the Lupi et al authors for the data, and was sort of waiting on that. Must follow up... $\endgroup$
    – Matt Hall
    Jan 10, 2015 at 12:49
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    $\begingroup$ Perhaps entice the author to join? In any case, this excellent answer highlights the difficulties sometimes encountered when trying to determine the origin of disasters. $\endgroup$
    – user889
    Jan 10, 2015 at 12:51

I just saw this question while looking at Lusi 9th anniversary news. As an author of several studies on this topic, wanted to say that the answer provided by Matt is an excellent summary of the triggering debate.

Two updates though.

1) I published a detailed reexamination and processing of the petrophysical and drilling data from BJP-1. This includes a discussion on the specific errors in the petrophysical model used in the Lupi et al. study and corrigendum.


Max Rudolph et al. have now also published a study in Geophysical Research Letters that undertakes similar modelling to that done in the Lupi et al. study and corrigendum. In this new paper, the effect of Yogyakarta earthquake is modelled using both the Lupi et al. corrigendum velocity model and my fully reprocessed and corrected velocity model. The results of the modelling indicate that the errors in the Lupi et al. velocity model significantly overestimate the effects of the earthquake. Interestingly, these results do also suggest that structure helps amplify the earthquake effects, but that the biggest influence is the increase in seismic wave amplitude that occurs when waves pass upwards from the fast volcanic/volcaniclastic layer into the Kalibeng clays. The domed shape causes little amplification, in contrast to the conclusions of Lupi et al. Regardless, the models all indicate that the effect of the earthquake is still very small, and much less than the known influence of the drilling kick. This new study can be found here:


2) We have an article in Nature Geoscience published:

http://www.nature.com/ngeo/journal/v8/n7/full/ngeo2472.html http://www.nature.com/ngeo/journal/v8/n7/extref/ngeo2472-s1.pdf

In this study, we use the drilling mud gas measurements from the BJP-1 borehole to directly test the hypothesis that an earthquake triggered liquefaction of the Kalibeng clays at Lusi (which is essential for the earthquake triggering hypothesis). Clay liquefaction is associated with release of gases and fluids. So, we examined the gas measurements coming from the BJP-1 well in the days before and after the Yogyakarta earthquake. Despite the BJP-1 well being open and exposed to almost the entire thickness of the clays, there is no increase in gas release in the 25 hours after the earthquake (the time period between the earthquake and the drilling kick that is alternatively argued to have triggered the disaster). This strongly indicates that the earthquake did not cause any liquefaction of clays at the Lusi location, and is the first actual direct measurements used to test the earthquake triggering hypothesis.

In addition, we examined the source of H2S from Lusi. H2S was observed coming out of the Lusi vent in its first few days of eruption. The earthquake triggering community has argued that this H2S comes from the Kalibeng Clays. In particular, the hypothesis is that the H2S has migrated from great depth into the Kalibeng clays via the Watukosek fault, with these deep hydrothermal fluids ‘priming’ the clays and making them prone to liquefaction. Yet, the gas measurements while drilling BJP-1 reported no H2S in the Kalibeng clays at all. H2S was first observed right at the bottom of the well, a few hours before the Yogyakarta earthquake. H2S was then observed during the drilling kick and then from the Lusi vent. Hence, the drilling gas data indicates that the H2S cannot have been sourced from the Kalibeng clays, and suggests that there is no evidence for deep hydrothermal ‘pre-charging’ of the clays. Rather, the H2S most likely comes from greater depths, near the bottom of the well (which is near or just in Carbonates, in which high H2S levels are commonly observed throughout the basin). This suggests that initial eruptive fluids from Lusi are essentially the same as those during the drilling kick 18 hours earlier, and that these fluids are tapping a deeper source than the Kalibeng clays. The drilling-trigger hypothesis is the only hypothesis that proposes such a deep initial fluid source, and the borehole makes a great pathway for deep fluids in the carbonates to suddenly escape through a 1000m thick sealing volcanic/volcaniclastic layer, pass through the Kalibeng clays and erupt at the surface.

Maybe this does not ‘close the argument’, but it does make the earthquake triggering hypothesis even more unlikely, and pose more questions that this hypothesis seems unable to answer (just like the question as to why the disaster would be triggered by the Yogyakarta quake, when there were many other larger quakes that had no effect). Furthermore, all these new measurements are fully in line with the drilling trigger hypothesis.

Like testing any competing hypotheses, you keep throwing data at them until they either fall down or keep standing. The drilling-trigger hypothesis is still standing strong; but the earthquake-trigger hypothesis has either fallen down, or is looking very shaky!

  • $\begingroup$ Mark, I am interested in reading your new paper. I thought you defended yourself quite well in the comments section of Matt's blog post. And although my institution's subscription to GSW is currently lapsed, I was intrigued by the abstract of the 2014 article. What a fascinating debate, and I'm glad that a healthy dose of scientific skepticism has been present throughout this process. Scientific questions should never be "closed", no matter how politically convenient it may be if they were. $\endgroup$
    – Ian
    Jun 11, 2015 at 22:01
  • $\begingroup$ Thanks Nez, Please send me an email (see my University of Adelaide staff page) and I'll happily send you the paper. Cheers, Mark $\endgroup$ Jun 13, 2015 at 11:37

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