Indonesia, an archipelago of thousands of islands, sits on the so-called Pacific Ring of Fire, a seismic activity hotspot There were no immediate reports of casualties or damage. JAKARTA, Indonesia: A strong earthquake has struck Indonesia’s Lombok island, which is not far from the tourist destination of Bali. The US Geological Survey said the quake had a magnitude of 6.4 and its epicenter was 1.4 kilometers (0.8 miles) southwest of Lelongken, Indonesia. It had a depth of 7 kilometers (4.4 miles). Authorities issued a yellow alert, which suggested that some casualties are a possibility. There were no immediate reports of casualties or damage. Indonesia is prone to earthquakes due to its location on the Pacific “Ring of Fire,” an arc of volcanoes and fault lines in the Pacific Basin. It is frequently hit by quakes, most of them harmless. However, the region remains acutely alert to tremors that might trigger tsunamis. In 2004, a tsunami triggered by a magnitude 9.3 undersea earthquake off the coast of Sumatra, in western Indonesia, killed 220,000 people in countries around the Indian Ocean, including 168,000 in Indonesia.