At least five people were killed and 40 others injured as two quakes measuring 6.5 and 6.9 on the Richter scale jolted Indonesia's Lombok Island where several previous tremors have already claimed over 400 lives since July, an official said on Monday.The jolts on Sunday morning and night amplified damages resulted from the 6.4 and 7.0 magnitude quakes hitting the island earlier on July 27 and August 5, head of emergency unit of disaster management agency Agung Pramudja said.The latest figure put the total death toll from the quakes since July 27 to at least 465.The official said that a preliminary report indicated that at least 200 houses were seriously destroyed by the temblor."The shakes incited significant damages and many residents have fled home and taken shelters in makeshift encampment," he told Xinhua.The official said that the assessment of the further risks of the jolts is being undertaken.No tsunami alert was issued.The first quake struck the island at 11.10 a.m. with epicentre at 32 km East Lombok of West Nusa Tenggara province in western parts of the island and a depth of 10 km, the agency said.The second one took place at 9.56 p.m. with an epicentre at 30 km northeast East Lombok district of West Nusa Tenggara province and a depth of 10 km, it said.Indonesia is prone to quake as it lies on a vulnerable quake-hit zone of "the Pacific Ring of Fire".