JAKARTA, Feb 15 (Reuters) - Several airports resumed operations on the heavily populated Indonesian island of Java on Saturday, a day after they were forced to close due to a volcanic eruption that sent a 17 kilometre (10 mile) ash cloud into the air.
More than 56,000 people were forced to flee their homes and four people were killed when Mount Kelud erupted late on Thursday in East Java province, coating cities and airports as far as 500 kilometres away in a layer of ash and stranding thousands of passengers.
"Four airports (of seven closed) are in operation now," said Handy Heryudhitiawan, spokesman at airport operator Angkasa Pura 1. "Juanda airport in Surabaya was reopened at 6 p.m. today."
Surabaya, about 90 kilometres (54 miles) north of the volcano, has Indonesia's third-busiest airport and is a major industrial centre. Its international airport was forced to shut down along with six others across Java in Bandung, Yogyakarta, Solo, Malang, Semarang and the major oil refinery town of Cilacap.
The environment ministry said on Saturday air quality near the volcano remained "very unhealthy" as government emergency response teams struggled to distribute food, masks and blankets to thousands of evacuees in shelters.
The national disaster mitigation agency said seismic activity at Mount Kelud had decreased, but that it was maintaining a 10 kilometre evacuation radius and the highest-level alert on the volcano.
Mount Kelud is one of 130 active volcanoes in the world's fourth most populous country, which sits along the "Ring of Fire" volcanic belt in the Pacific Ocean.
At least 11 people were killed earlier this month in the north of the island of Sumatra when Mount Sinabung erupted. The volcano has been spewing lava and ash for months, forcing thousands to flee the area and destroying crops.
(Reporting by Chris Nusatya, Writing by Kanupriya Kapoor, Editing by Matt Driskill)