MANILA(UPDATE)—Houses in Batanes are not built to resist earthquakes, reason why structures collapsed and lives were consequently lost during a tremor in the province Saturday morning, Phivolcs director Renato Solidum said.

Solidum said Batanes houses, most of which were built during Spanish colonial times, are made of limestone, which can quickly disintegrate once they tremble.

"Ang mga bahay na nasira 'yung mga luma na mga bahay, ang iba pa nga panahon ng Kastila na yari sa limestone. Wala pong bakal 'yan, patong-patong at ang limestone ay madaling matunaw kaya nagiging marupok 'yan in time," Solidum told DZMM radio Saturday.

" 'Yun 'yung naging sanhi ng pagkamatay at pagkasugat ng mga tao."

Limestone houses, known for being wind-resistant, are meant to brave conditions in a region known to attract powerful storms. But in the event of an earthquake, such structures are considered weak.

"Kahit malakas ito, matibay sa hangin, hindi masyado ito nauuga. Pero 'pag lindol na ang pag-uusapan, gagalaw 'yung pinaka-paa ng bahay at tutumba 'yung mga wall," Solidum added.

Eight people died and 60 others were injured after two earthquakes in the magnitude-5 range hit Batanes. The first, one registered at 5.4, struck at 4:16 a.m. at a depth of 12 kilometers northeast of Itbayat town.

• Magnitude 5 quake jolts Batanes

Three hours later, a second one at magnitude-5.9 happened at about 19 kilometers off Itbayat.

• Magnitude 5.9 quake rocks Batanes

According to Solidum, 64 quakes were recorded between the two major jolts.

He said local government engineers in the islands must make sure Igbayat residents follow the national building code and use prescribed building materials.

"(So) next time there is a strong earthquake, they (Igbayat) will be less vulnerable," Solidum said.