MANILA, Sept. 15 (Xinhuanet) -- A moderate earthquake measured 4.3on the Richter scale hit northern Luzon island in the northern Philippines before dawn Monday, the Philippine Institute of Volcanology and Seismology (Phivolcs) announced.

　　The epicenter of the quake was estimated 78 km northwest of Laoag city, Phivolcs Director Dr. Renato Solidum said, adding thatthere were no reported casualties or damage to property as a result of the quake.

　　Solidum said the quake was tectonic in origin.

　　The Eurasian plate slid under the Manila trench, which stretches from the northwest of the Batanes islands at the tip of Luzon island to west of Mindoro island in Southern Luzon, is in a process called "subduction," he said.

　　Solidum belittled the possibility for the quake to cause a tsunami, saying a tsunami only occurs when the earthquake reaches intensity 6. Enditem