Reports of villages flattened are coming from there, said Antorizon of the West Sumatra disaster management agency, who like many Indonesians goes by one name. The first pictures from North Pagai Island showed damaged and flattened structures. Monday's quake generated a significant tsunami, the Pacific Tsunami Warning Center said. Some of the missing might include people who are unaccounted for after fleeing to higher ground, said Henri Dori Satoko, head of the Mentawai Islands parliament. Though communication poses a challenge in the remote area, some witnesses in West Sumatra reported seeing a wave 6 meters -LRB- nearly 20 feet -RRB- high. Other reports described the tsunami as being about 3 meters -LRB- almost 10 feet -RRB- high. At least one village with a population of about 200 people was swept away, with only 40 people recovered, Satoko said. The quake struck at 9:42 p.m. Monday, triggering a tsunami warning. Its epicenter was 240 kilometers -LRB- 150 miles -RRB- south of Padang, at a depth of 20.6 kilometers -LRB- 12.8 miles -RRB-, according to the U.S. Geological Survey. The magnitude was revised upward from a preliminary magnitude of 7.5. On Mentawai, a -LSB- tsunami -RSB- warning was issued seven minutes after detection of earthquake, which is what the existing system is capable of doing. Preliminary report indicates the destructive waves hit the Mentawai Islands