PAHOA, Hawaii — Geologists warned Wednesday that Hawaii’s Kilauea volcano could erupt explosively and send boulders, rocks and ash into the air around its summit in the coming weeks.

The risk will rise as lava drains from the summit crater down the flank of the volcano, and explosions could occur if the lava drops below the groundwater level, the U.S. Geological Survey said. There’s potential for ash and sulfur dioxide emissions.

Kilauea is one of the world’s most active volcanoes.

It has destroyed 36 structures since it began releasing lava into fissures that opened in a Big Island neighborhood about 25 miles from the summit crater. There are now 14 of the fissures spread through Leilani Estates.

In the weeks ahead, the volcano could eject blocks up to 2 yards in diameter a little less than a mile away, the USGS said. It may also send pebbles shooting into the air several miles away, the USGS said.

The receding lava lake resembles conditions seen before a major eruption in 1924, said Tina Neal, scientist-in-charge at the USGS Hawaiian Volcanoes Observatory. That explosion killed one person and sent rocks, ash and dust into the air for 17 days.

No one lives in the immediate area of the summit crater. But people are continuing to visit Hawaii Volcanoes National Park, which includes the crater and surrounding region.

Park spokeswoman Jessica Ferracane said the park will be evacuated before conditions develop for an explosive eruption at the summit.

In the Lanipuna Gardens subdivision, police went door-to-door Tuesday to roust residents near two new volcanic vents emitting dangerous gases in areas where lava has poured into streets and backyards.

Authorities previously ordered nearly 2,000 residents to leave Lanipuna and neighboring Leilani Estates in the mostly rural district of Puna. But some ignored the order and stayed to watch over their property.

In recent years the volcano has mostly released lava in hard-to-reach areas inside a national park or along the coastline. But last week, vents popped open and released lava, gas and steam inside neighborhoods.