No abstract

From 28 to 30 September 1965 there occurred a moderately violent phreatomagmatic explosive eruption of Taal Volcano in southwest Luzon, Philippines, about 60 kilometers south of the city of Manila (Fig. 1). The eruption covered an area of approximately 60 square kilometers with a blanket of ash more than 25 centimeters thick. Present records of casualties show that 51 bodies have been recovered and 138 persons are missing. The center of the eruption was on the southwest side of Volcano Island, an irregularly shaped island about 5 kilometers in diameter, in Lake Taal. Lake Taal is approximately 20 kilometers in diameter. Some authors consider it a caldera lake that occupies a depression formed by collapse of a former volcanic edifice of unknown height (1).Since the year 1572 there have been 26 explosive eruptions of Taal Volcano. All have occurred on, or very close to, Volcano Island. Before 1749 most of the eruptions took place on the northwest or southwest part of the island. The 12 eruptions that occurred from 1749 to 1911 were centered in the large crater in the middle of the island. The 1965 eruption is the first since 1749 to be located on the flanks of the island.The last previous eruption, that of 1911, was far more violent. It not only obliterated most life on the island but caused extensive damage to life and property on the shores of Lake Taal, except south and southeast of Volcano Island (2). Approximately 1335 persons lost their lives.