Powerful earthquakes jolted the Indonesian island of Sulawesi on Friday, destroying houses and killing at least one person. An official said widespread damage was expected and urged people to stay outdoors because of the danger of strong aftershocks. The US Geological Survey said the strongest quake had a magnitude of 7.5 and was centered at a depth of six miles (10 kilometers) about 35 miles (56 kilometers) northeast of the central Sulawesi town of Donggala. It briefly triggered a tsunami warning. Injury victims received treatment at Poso District General Hospital, both in corridors and on a nearby field.