An earthquake measuring 3.9 on the Richter scale jolted Palu city and Donggala district in Central Sulawesi province on Thursday night, forcing many residents to rush outdoors for fear of being trapped in the debris of damaged houses, ANTARA reported. The epicenter of the quake which struck at 11.49 p.m. was located 19 km south of Palu, capital of Central Sulawesi province, at a depth of 24 km, the local meteorology and geophysics office said. There was no immediate report of casualties or material damage. Thursday's quake was the third to hit the province in the past 39 days.