MOUNT MERAPI, Indonesia — Rescuers scoured the slopes of Indonesia’s most volatile volcano for survivors Wednesday after it was rocked by an eruption which killed at least 30 people, including an old man who refused to abandon his ceremonial post as caretaker of the mountain’s spirits.

Authorities warned the thousands who fled Mount Merapi’s wrath not to return during Wednesday’s lull in volcanic activity, but some villagers were desperate to check on crops and possessions left behind. In several areas, everything — from the thinnest tree branch to couches and chairs inside homes — was caked with ash that looked like powdery snow.

The latest blast Tuesday night eased pressure that had been building up behind a lava dome perched on the crater. But experts warned the dome could still collapse, causing an avalanche of the blistering gas and debris trapped beneath it.

“It’s a little calmer today,” said Surono, the chief of Center for Volcanology and Geological Hazard Mitigation. “No hot clouds, no rumbling. But a lot of energy is pent up back there. There’s no telling what’s next.”

Mount Merapi, which translates as “Fire Mountain,” has erupted many times over the last 200 years, often with deadly results. In 1994, 60 people were killed, while in 1930, more than a dozen villages were incinerated, leaving up to 1,300 dead.

Still, as with other volcanoes in Indonesia, more than 11,000 people call its fertile slopes home.

Even as rescue officials contended with the volcano — one of 129 under watch in Indonesia, the world’s largest archipelago — officials hundreds of miles (kilometers) away were trying to assess the impact of a powerful earthquake off Sumatra island that triggered a tsunami, leaving several hundred missing or dead.

The twin disasters happened hours apart in one of the most seismically active regions on the planet, prompting President Susilo Bambang Yudhoyono to cut short a state visit to Vietnam so he could help oversee the response.

Officials said earlier that by closely monitoring the volcano they hoped they could avoid casualties, but the death toll was quickly rising.

Aris Triyono, of the national search and rescue agency, said his teams were searching the southern slope of the mountain, which has been pounded by rocks and debris, in search of victims and survivors.

Dr. Teguh Dwi Santosa, a doctor at a local hospital, said the death toll climbed to 30 on Wednesday, and 17 had been hospitalized, mostly with burns, respiratory problems and other injuries.

Among the dead was Maridjan, an 83-year-old man who had been entrusted by a highly respected late king to watch over the volcano’s spirits.

“We found his body,” said Suseno, a rescue worker, amid reports that the old man was found kneeling face-down on the floor, a typical prayer position.

Maridjan, who for years led ceremonies in which rice and flowers were thrown into the crater to appease spirits, has angered officials in the past by refusing to leave during eruptions.

They accused him of setting a wrong example and stopping other villagers from leaving, but Maridjan always said he would only go if he got a sign from the long-dead king who appointed him.

Though thousands of villagers streamed into makeshift emergency shelters after Tuesday’s powerful eruption, many defied official warnings and started returning Wednesday, saying they had to tend to their crops and protect their homes.

“We’ll do everything we can to stop them,” said Hadi Purnomo, the district chief in Sleman, describing several formerly plush villages south of the crater as “death zones.” “There’s no life there. The trees, farms, houses are scorched. Everything is covered in heavy gray ash.”

Several other areas, however, were virtually untouched.

“I keep thinking about what’s happening up there,” said Hadi Sumarmo, who has a farm in Srumbung, a village three miles (seven kilometers) from the cone. “I just want to go back to check. If I hear sirens, I’ll get out again quickly.”

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Associated Press writers Niniek Karmini, Irwan Firdaus and Ali Kotarumalos in Jakarta contributed to this report.