The morphologically youthful Iraya volcano, at the north end of Batan Island, is the northernmost active volcano in the Philippines.  Iraya is the most prominent feature of the 20-km-long, dumbbell-shaped Batan island, located in the Luzon Strait between Luzon and Taiwan.  The 1009-m-high Quaternary stratovolcano has a 1.5-km-wide summit crater, which is largely filled by a younger cone that forms the summit of the volcano.  Observed late-Pleistocene and Holocene products of Iraya are exclusively explosive.  The youngest dated unit of Iraya is a pyroclastic-flow deposit radiocarbon dated at about 1500 years ago (Richard et al., 1986).  The Philippines Institute of Volcanology and Seismology (2004-) listed an eruption in 1454 AD of unspecified character.