Thread by @CriticalStress_

On this day in 2006, the 'Lusi' Mud Volcano was born. This was the start of the worst mud volcano disaster in history. A truly unique tragedy.

Lusi is today's #MudVolcanoOfTheDay & the third thread in the #MuddyMay 'Mud Volcano Disasters' series.

Video courtesy of @Greenpeace

The Lusi mud volcano was born before dawn on the 29th May 2006. Hot mud started gushing out of a new hole in the ground in a rice paddy in the town of Sidoarjo.

At rates of ~5000 cubic meters per day, the mud quickly started to flood nearby lands.

The Lusi mud volcano is located in Sidoarjo, which is just south of Surabaya, the second largest city on Java.

Location here:
goo.gl/maps/83vZQurU3…

This was the first time that a new major mud volcano had erupted in the middle of an essentially urban area.

The initial ~5000 cubic meters per day from Lusi was bad.

But it got much much worse.

In early August, the eruption became extremely violent - and started throwing out mud at rates of 100000-180000m^3/day.

That's fast enough to fill an olympic swimming pool every 25 minutes.

Authorities had been trying to contain the mud flow by rapidly building a series of earthen walls.

These defences didn't stand a chance under the increased onslaught of mud.

The dams failed, and suburbs were flooded and thousands of people had to flee.

Video from Greenpeace

All up, approximately 7 square kilometres of a city were buried in mud. ~40000 people were permanently displaced - many fleeing their homes so quickly they lost everything.

Houses, factories, mosques, farms, livelihoods - all gone.

It did not stop there. In fact, the key thing to keep in mind about this disaster is that it still has not stopped!

The mud volcano has been erupting continuously, and violently, for 13 full years.

Most geological disasters have an end. The quake or flood or storm occurs and causes huge damage.

But people can go back home. They can rebuild.

Not with Lusi. What were people's homes is now a sea of mud. These victims are permanently displaced - refugees.

Before and after:

And yet, even after all that devastation, and the permanent loss, it could still get worse.

On the 22nd November 2006, subsidence from the eruption caused a major gas pipeline to rupture.

Authorities rushed to cordon off the area - when the gas ignited. 14 died, 13 were injured

There have been further deaths over the years. Several deaths of workers involved in building and maintaining the dams that hold back the mud flow. A few years ago, a young child was killed after a dam breach.

There has also been a large environmental cost.

Authorities have built dams higher and higher to contain the flow. But, have also sluiced and diverted vast volumes of mud into the nearby Porong River.

You can see the river colour turn grey where the mud pours into the river.

What has also made this disaster unique is the controversy over its cause.

Most people do not consider this the Lusi mud volcano to be a 'natural' event.

Most people conclude that this disaster was the result of an accident in a nearby gas exploration well.

Its here that this disaster takes on political dimensions.

The well in question, Banjar Panji-1, was being operated by a company owned by one of the richest and most powerful people in Indonesia - who at the time was a government minister and leader of a major political party.

Within days of Lusi starting, fingers were pointed at the nearby well. Soon, a partner company in the well started taking legal action.

As the disaster got worse and worse, the company operating the well became more vocal in claiming the well had nothing to do with Lusi.

The company claimed that the culprit was different disaster - the huge Yogyakarta earthquake that had struck two days prior over 250km away. A tragedy that killed over 5000 people.

The scientific controversy surrounding the Lusi disaster is still essentially a debate between these two different proposed 'triggers' for the mud eruption - a drilling accident or the Yogyakarta earthquake.

The petroleum company engineers and some seismologists argue that the shaking from the Yogyakarta earthquake caused liquefaction underground, resulting in slip of a fault and mud flow to the surface.

Many others, myself included argue that a massive well control incident that occurred the day before Lusi erupted resulted in underground faulting or fracturing, and allowed high pressure water, mixed with clay, to erupt at the surface.

Now, we know a lot about mud volcanos, and regularly see them erupting shortly after nearby earthquakes. So, it is not far fetched to think a earthquake might trigger this disaster.

However, the evidence doesn't stack up...

In particular, the seismic energy density from the Yogyakarta quake at the Lusi location was smaller than previously observed to initiate any new mud volcano.

Also, why that earthquake? There had been 13 earlier quakes that were more likely to be a trigger and they had no effect

Finally, the quake-trigger model requires liquefaction and the release of huge amounts of gas underground.

But, the nearby well, which was actively monitoring for underground gas, observed no gas increases in the ~24 hours after the quake.

So, while some scientists still argue for a quake-trigger for Lusi, there isn't any strong evidence. The quake was too small when compared to others that have triggered mud volcanoes, bigger quakes had no affect and the well showed no signs of underground activity from the quake.

On the other hand, there is a lot of evidence for a drilling trigger.

The Banjar Panji-1 well suffered a major well control incident on the morning of the 28th of June, a day before Lusi started. This resulted in large amounts of muddy water erupting from the well.

We also know that drilling accidents can result in blowouts and mud eruptions, sometimes even several kilometres from where the well is drilled.

Here is an example from Central Java.

When the eruption occurred at the well, the drillers took normal action (eventually) to close the blowout preventer - sealing the well at the surface.

But this doesn't stop the blowout - fluids rush into the well underground and fluid pressures increase inside the well...

If the pressures inside the well exceed that required to break the rocks, then the fluids fracture the rock and create their own new pathway to the surface.

The pressures measured in the well after the well control started tell a story of a fracture propagating to the surface.

The well even records the exact moment Lusi first erupted - when pressures trapped underground suddenly become zero as the fluids reach the surface.

The eruption also contained gases that were only seen at the very bottom of the well - a clear 'fingerprint'.

The drillers, believing the mud eruption was a blowout, made several attempts to kill the eruption by pumping dense mud and then cement down the well.

The Lusi eruption slowed down when they pumped, and increased when they stopped.

Lusi was in direct connection with the well...

We don't know everything about what happened on the rig. But, the data and records are conclusive that a major well control event occurred, the event was big enough to break the formation, the well recorded fracture growth to the surface and was in communication with the eruption

In many ways, there's parallels between this debate and others like global warming.

There's a lot of evidence supporting one hypothesis and, while uncertainties and unknowns exist, very little data against it.

In contrast, alternative ideas are really not supported by evidence.

Sadly, while scientists debate, the people displaced by this disaster suffered. The company wouldn't pay the compensation they were ordered to. Few aid agencies would help what was seen as an industrial accident. Finally, after 10 years, the government essentially paid the victim

So much more still to say, but I need to wrap this up and get to bed.

I hope you found this special #MuddyMay thread on the Lusi mud volcano tragedy interesting, and a terrible reminder of the power that mud volcanoes have, and the damage that industrial accidents can cause.