An earthquake swarm began 6 May in the vicinity of Canlaon. The number of earthquakes recorded per day on nearby seismographs reached a peak of 108 on 19 May, then seismicity began a gradual decline. In late June, volcanic shocks continued to occur at a rate of about 40/day. As of 27 June, a total of 2,652 events had been recorded. No surface volcanism has been reported with this earthquake swarm.

Geological Summary. Kanlaon volcano (also spelled Canlaon) forms the highest point on the island of Negros, Philippines. The massive andesitic stratovolcano is covered with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km SW from Kanlaon. The summit contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller but higher active vent, Lugud crater, to the south. Eruptions recorded since 1866 have typically consisted of phreatic explosions of small-to-moderate size that produce minor local ashfall.

Information Contacts: O. Peña, COMVOL, Quezon City.