Under the volcanoes

PAUL KNOX, The Globe and Mail,Thursday, December 23, 1999

Lloa, Ecuador -- Green pastures and forests sweep up the mountainside, yielding only at the summit to a jumble of rock.

The sky is brilliant blue, the clouds puffy as they linger on the slope. Lloa's few streets, near-deserted, give no hint of alarm.

But underneath this placid landscape is a bubbling, trembling mass of molten rock, water and gas that threatens to blow sky-high for the first time in more than 300 years.

This is the Guagua Pichincha volcano, 12 kilometres west of Quito, Ecuador's capital city. Inside that craggy 4,784-metre summit is a roiling caldera, or large crater, and beneath the caldera is a column of magma that is bursting to get out.

When it does -- and volcano experts here tend to say when, not if -- it could dump a thick layer of ash several centimetres deep on Quito, a city of 1.5 million people.

Minor explosions have already spread a fine carpet of grit on the city several times this year. It has forced school closings, and the international airport shut down for a week last month.

"So far, it's only been a few millimetres, but even that has caused physical and psychological damage," says Minard Hall, a volcanologist at Ecuador's Institute of Geophysics. "With several centimetres, it could shut down the city pretty well."

About 150 km to the south, the hot-spring resort town of Banos has already been shut down. A second volcano, 5,023-metre Tungurahua, has been belching fire and rock since September, forcing authorities to order 25,000 people out of their homes.

Scientists say clouds of red-hot gas and dust from Tungurahua could turn Banos houses into instant fireballs, while lava flows could block two nearby rivers and cause massive flooding.

But those uprooted are getting restless. Some are demanding to be allowed back home. Others want money to start businesses in nearby Ambato, where they are temporarily housed.

About 1,000 farmers who live on the slopes of Pichincha have also been forced to move. They, too, have had enough.

"Why should we be afraid of the volcano?" asked Maria Altamirano, a 41-year-old mother of eight from the village of San Luis who has been living in tents and temporary shelters for most of the autumn. "We've always heard the noises."

A few kilometres away, along a rutted track lined with thick foliage and clumps of pampas grass, lies the hamlet of San Jose. It has been evacuated, but residents are allowed in for a few hours' field work each day.

It's not enough, said Maria Agustina Chiluisa Leon, who tends potatoes, beans, corn and barley as well as a few cows on her family's five hectares. "We'll be left without anything to eat next year."

Ms. Chiluisa, wizened and a little stooped after 60 years and eight children, has moved four times this fall. In September she was taken to a shelter in nearby Chichigayo. She moved back home for two weeks, then to a church down the road in El Cinto.

On Dec. 11, she was transferred to Lloa -- which itself was evacuated earlier, but which authorities now say is safe enough to harbour its own people as well as those from more dangerous parts of Pichincha's slope.

Volcano threats are hardly new to Ecuador. At least 18 cones in the Andes have been active in the past 10,000 years. Among the world's cities directly threatened by volcanoes, Quito is the second largest, after Naples in southern Italy.

It is unusual for two peaks in different parts of the cordillera to threaten at the same time. And the volcano crisis is piled on to Ecuador's worst economic news in decades.

Those displaced by the threat of eruption are also coping with a 150-per-cent annual inflation rate, high unemployment and a sharply devalued currency.

Guagua (Baby) Pichincha -- reputedly named because it was born during an eruption of nearby, inactive Rucu Pichincha -- last exploded in 1660. Tungurahua also had a major eruption in that year, along with others in 1773, 1886 and 1916-18.

Dr. Hall, a San Francisco-born geologist who has lived in Ecuador for 27 years, says the volcanoes pose distinct threats because their structure, chemistry and setting are different. His metaphor is graphic: "Pichincha is constipated; Tungurahua has diarrhea."

Pichincha's magma has a higher silicon content, which makes it thicker. It surges up to the caldera, forming molten domes and sending clouds of steam and ash as high as 15 km into the air.

But underneath, trapped by the thick domes that eventually cool and harden, are layers that include more gas and water. "At some point it's possible that the more liquid and volatile parts of the magma will erupt," Dr. Hall said.

Tungurahua's magma doesn't form viscous domes. It spurts out of the caldera and tosses up glowing rocks -- a spectacular display at night.

Pichincha is also a bundle of nerves. Echosonogram monitors have picked up tens of thousands of microearthquakes since September -- roughly one every three or four minutes. "They are not felt by people but they tell us what's going on."

Tungurahua is less co-operative. "The volcano is not giving us as much scientific information that would allow us to predict with some certainty what could go on in the near future," Dr. Hall says.

That makes the institute's scientists more conservative in urging evacuations. Their nightmare is a Tungurahua eruption that sends lava and pyroclastic flows -- clouds of rock, dust and gas as hot as 700 degrees -- surging down the mountainside toward Banos and its townspeople.

"Once you see the event, there's no way to get them out in time," Dr. Hall says.

Banos was evacuated more than two months ago. Tungurahua is still biding its time, and the displaced are wondering why they had to move when no one did in 1916-18.

The answer, Dr. Hall says, is that Banos is bigger now. Houses have been built on earlier lava flows.

Nevertheless, he adds, if the mountain stays relatively quiet, the pressure to return will be too great to resist. "We just hope the volcano will give us the signs, and we correctly interpret them, to give enough warning for people to get out."

The institute wants conditions for a return, including a good alarm system and soldiers stationed in Banos with trucks that can move people out quickly.

Lava gushing out of Pichincha is expected to flow westward, away from Quito. But a heavy ash eruption could clog water pipes and sewers in the capital, sicken anyone with respiratory problems and collapse weak roofs.

The ash would also land on the hills above the city, and Quito's frequent rains could send tonnes of sludge coursing down toward the suburbs.

Quito mayor Roque Sevilla is taking the threat seriously, Dr. Hall says. He asked for and got control of disaster preparations.

Some foreign firms operating in Ecuador have sent the families of expatriate employees out of the country until the threat subsides.

But Guagua Pichincha isn't a deadly volcano. Its only victims in recent years have been two volcanologists caught in a 1993 explosion after they walked into the caldera to take rock samples after unusual activity.

On the plane to Quito this month, deputy agriculture minister Francisco Dammer told of sending crews out on one of his ranches to shake and wash volcano ash off the grass. He feared it would harm his cattle.

Don't bother, say the people on Guagua Pichincha's southwest flank who've lived all their lives with the big baby's burps and gurgles.

"The animals are more intelligent than we are," said 42-year-old Rosa Quinga. "They just knock the ashes off the grass and eat it."

Ms. Quinga's husband, Rodrigo Viracucha, is one of two "guardians" of Guagua Pichincha. In quieter times he kept track of hikers trekking to the summit. Now he peeks into the caldera and radios volcanologists to tell them what's going on.

They believe they know the volcano well enough to size up any danger, but Dr. Hall isn't so sure.

"We're suggesting he shouldn't be spending nights up there," he says. "We're constantly telling them to get the hell out."