JUDY WOODRUFF: Next: how science, mysticism and superstition all play a role in Indonesia's reaction to a deadly volcano.
Hundreds of people were forced to flee this week from the fallout of the country's most volatile volcano, which began erupting anew in October.
NewsHour science correspondent Miles O'Brien has the story from Indonesia.
MILES O'BRIEN: Near the summit of Indonesia's most active volcano, the once lush terrain is now a memory buried beneath a landslide of newly minted rock and soil.
For many people in Yogyakarta, Mount Merapi, the mountain of fire that looms over the city, has become a macabre, otherworldly destination for a Sunday ride. For thousands of volcano refugees, it is, quite simply, home, or at least it as.
No one is certain when, or if, they will ever return. The only home and farm Ranto Utomo (ph) has ever known used to be here.
"Everything is destroyed, totally destroyed," he told me, "no house, no cow. Our village is totally destroyed."
It was the worst eruption here in 140 years. It began on October 26, when Merapi blew its top, shooting lava, hot gas, boulders and ash down the mountainside at the speed of a jet airplane, a scalding-hot, lightning-fast landslide scientists call a pyroclastic flow.
Take a look at this. This gives you a sense of the force, the devastation that is created by one of these pyroclastic flows. It came down this way, gas heated to 1,800 degrees Fahrenheit, huge boulders the size of houses moving at 450 miles an hour.
This is what's left of the town of Kali Adem. About three dozen people decided to stay. They didn't have a chance. They were there despite evacuation orders from the man known only as Surono, Indonesia's chief volcanologist, arguably the busiest practitioner of that profession in the world.
At a command center in the city, he watched seismographs connected to instruments that encircle the volcano. They were telling an unambiguous story of impending disaster. The magma beneath Merapi's crusty lava dome was on the move, causing swarms of intense tremors. Merapi was warming up for an epic performance.
SURONO, Indonesian Volcanology Center: Bum, bum, bum. Bum, bum, bum, like -- like Mozart, you know?
MILES O'BRIEN: It was clear to Surono the crescendo would be discordant and historic.
So, you knew it was going to be a big one?
SURONO: Yes, yes. So, I call every three hour to the local government, OK, quick, quick, quick, quick to evacuate the people.
MILES O'BRIEN: Right.
Did they listen?
SURONO: Yes. Yes.
MILES O'BRIEN: With one notable exception. Another respected man with one name, Marijan, refused to leave, insisting there was no danger. His words carried weight because he was the so-called gatekeeper of the volcano.
In the world of Javanese mysticism, the gatekeeper protects the people of Yogyakarta by communicating with the spirit of the volcano, Grandfather Merapi.
BERNARD ADENEY-RISAKOTTA, Gadjah Mada University: He's a very powerful deity who is really behind the fertility of this land.
MILES O'BRIEN: Bernard Adeney-Risakotta is a professor of the social scientific study of religion in Yogyakarta.
BERNARD ADENEY RISAKOTTA: For Javanese, Central Java, Merapi is the most holy place in -- it's like the center of the universe.
MILES O'BRIEN: Marijan earned huge credibility and nationwide fame in 2006, when he defied another eruption prediction and remained on Merapi. Instead of an eruption, there was an earthquake. And, before long, he was endorsing an energy drink.
But, this time, Marijan was no match for the pyroclastic flow. His death has shocked the Javanese and, frankly, bolstered Surono's credibility. Many here are now calling him the new gatekeeper.
People have superstitions, though, right?
SURONO: Yes, but Merapi logic is more sure than superstition. I believe the Merapi logic not believe the voodoo, something like that, no.
MILES O'BRIEN: Merapi has killed more than 300 during this eruption and is currently the most menacing of 129 active volcanoes across the Indonesian Archipelago.
Another Java volcano, Bromo, is also in the midst of a big eruption. The islands of Indonesia formed at the boundary between tectonic plates of the Earth's crust, part of the Ring of Fire, as it is known. It goes all the way around the Pacific and is home to three-quarters of the world's volcanoes and 90 percent of the earthquakes.
Here in Indonesia, the Indo-Australian plate is crashing into the Eurasian plate. As one plate moves beneath the other into the Earth's mantle, it changes the pressure and adds ocean water, making the mantle melt. This is what feeds volcanoes and earthquakes, and no place more so than Indonesia.
SIMON WINCHESTER, author, "Krakatoa": So, really, as a test bed of the horror show that volcanoes can be, Sumatra and Java is it.
MILES O'BRIEN: Geologist and author Simon Winchester wrote the book "Krakatoa: The Day the World Exploded." The eruption of the Krakatoa volcano in Java in 1883 killed at least 40,000 and is considered the loudest noise ever heard in recorded history.
At the time, many Javanese believed it was a sign the gods were angry with Dutch colonial rule.
SIMON WINCHESTER: There was a rebellion in 1888, with Krakatoa being the watchword. And local Muslims drove out or began the process of driving out the Dutch, who eventually left, leaving in their wake what is now the most populous Islamic country on Earth, the Republic of Indonesia.
So, one can say that the successful rise of Islam and the expulsion of Dutch colonialists was triggered by a volcanic eruption.
MILES O'BRIEN: Certainly, much has changed since Krakatoa, but, in the 30 years Surono has been at it, the science of volcanology has improved dramatically.
Besides seismometers, a well-monitored volcano like Merapi is outfitted with lasers that can measure the movement of the lava dome. When an eruption is imminent, it will expand like a balloon before bursting. But knowing precisely when that may happen, that is still beyond the reach of science.
So, it's a science, but, in some respects, it's inexact, isn't it, right, right?
SURONO: Yes, yes, yes, yes, yes, yes. Inexact, I think not exactly.
MILES O'BRIEN: You cannot tell me what time and day, right? Right?
SURONO: Yes, yes, this is right.
MILES O'BRIEN: This is what people want?
SURONO: Yes, yes.
MILES O'BRIEN: So, how good are the predictions these days?
JOHN EICHELBERGER, volcanologist, U.S. Geological Survey: Reasonably good. We like to use the word forecast.
MILES O'BRIEN: That's volcanologist John Eichelberger of the U.S. Geological Survey. I sat down with him before I left for Java to learn the state of the volcanology art.
It turns out they are looking for data more and more in space. GPS and radar satellites now provide much more precise information on the movement of lava domes. And weather satellites help monitor and track ash plumes and gases as they spread. Scientists are also experimenting with drones that can fly though a smoldering volcano to sniff for sulfur dioxide, a surefire signature of an eruption.
But, even with all this, Eichelberger says it is still harder than predicting -- forecasting the weather.
JOHN EICHELBERGER: It's not like saying that a hurricane is likely going to -- a bunch of tracks, and it will be here two days from now.
MILES O'BRIEN: The question now is, when will Merapi be done erupting? No one knows the answer for sure. While we were up there, as a matter of fact, we were told to evacuate in a hurry. There was some concern more lava was on the way.
We didn't waste any time getting away from the summit.
So, it must be difficult to know when to say it's over?
SURONO: Yes, the same -- the same problem when Merapi will erupt -- the same problem. It might be not so -- so -- more difficult -- more difficult to downgrade it.
MILES O'BRIEN: For the mystics of Java, Surono's data is of little concern.
Damardjati Supadjar sees the fiery result of shifting plates and a dead gatekeeper as a clear message from the gods.
Are the spirits unhappy? Are there evil spirits? What's the word?
DAMARDJATI SUPADJAR, Javanese Mystic: Yes, yes, yes. There is also a warning. We have got a spiritual revolution.
MILES O'BRIEN: There is little talk of this among refugees at the soccer stadium. Their worries have come home, because they cannot.
So, you lived on a volcano. Did you think this -- did you ever think about this happening one day?
"I never thought about that," she said, "never thought it would happen this big, to destroy our village, our homes."
If the people here under the stands in this stadium had listened to the gatekeeper, Marijan, they very likely wouldn't be here today. And, yet look at this, a little piece of irony. This is a shrine to the gatekeeper, lots of paintings done by the kids here. And look at this, another piece of irony, in spite of all that's happened: "I love Merapi."
Boy, if it were me, I would be crying, but not you. How come?
"You don't have to cry," he said. "If everyone's crying, it would become a flood. I feel very calm, because the cow and the house and everything, Allah lent it to me. So, now he is taking it back, and that is OK. As long as Allah gives me health, happiness and patience, I will start again."
Indonesia is famous for its many tongues. Here in Java, it seems, they speak the languages of religion, mythology and science all at once. It sounds like a jumble of contradictions, but, apparently, it works. The proof may be in this most unlikely smile.