JAKARTA—The Semeru volcano on the Indonesian island of Java erupted on Saturday, killing one person, injuring at least 35 and trapping some people in buildings as it spewed out huge clouds of smoke and ash, officials said. Videos shared by emergency officials showed residents running as towering plumes of smoke and ash blanketed nearby villages in East Java province. The deputy chief of Lumajang district, Indah Masdar, told a news conference one person had died and 41 people had suffered burn injuries. The disaster mitigation agency (BNPB) said later that 35 patients were being treated at local medical facilities. Indah asked for helicopters to rescue people trapped inside buildings. “We’re in big distress,” she said, adding there were at least 10 people trapped. “It’s harrowing, their families are all crying.” Thoriqul Haq, district head of Lumajang, said a number of sand miners were trapped near mines, but did not give …