Lake Pinatubo
Interesting facts
- In 1992 a new lava dome rose inside the young lake as an island, only to be drowned later as the water kept rising.
- Before engineers cut a drainage notch in 2001, the lake was rising by about a metre a month, and some 9,000 people were evacuated as a precaution.
- In 2002 heavy monsoon rains overtopped the artificial drainage channel and set off mild lahars on the slopes below.
- The lake is fed only by rain falling on a catchment of about 5 km², and its overflow drains into the Bucao River.
- The centre of the caldera lies about 1 km north of where Pinatubo's summit stood before 1991.
- The 1991 eruption coincided with Typhoon Yunya, whose winds swept ash in all directions while the eruption column rose about 35 km high.
- By the volcano's own standards 1991 was modest: the eruption that gave birth to modern Pinatubo around 79,000 BC was about five times larger.
- Before 1991 the mountain was so overgrown by rainforest that most people did not realise it was a volcano at all.
- A 2008 scientific study linked the Aeta legend of a lake destroyed by an explosion to a real prehistoric lake dammed by volcanic mudflows.
Why it is worth it
Lake Pinatubo fills the crater left by one of the most violent eruptions of the 20th century. On 15 June 1991 Mount Pinatubo, on the island of Luzon, exploded after roughly five centuries of quiet, in an eruption rated 6 on the Volcanic Explosivity Index and surpassed in that century only by Novarupta in Alaska in 1912. It expelled around ten cubic kilometres of magma and some 20 million tonnes of sulphur dioxide, a haze that lowered global temperatures by about half a degree Celsius over the following two years. The summit, once about 1,745 metres high, collapsed into a caldera around 2.5 km wide.
Within months, by September 1991, rain had begun to pool in the new caldera. At first the lake was small, hot and strongly acidic, close to pH 2 at about 40 degrees; heavy rains gradually diluted and cooled it, and by 2003 the water was near 26 degrees with a pH of about 5.5. Today the lake lies at roughly 900 metres above sea level, covers about 1.8 square kilometres and was measured at 95 to 115 metres deep in 2002, its colour shifting between turquoise, blue and green against the grey ash cliffs. In 2001 engineers cut a notch in the crater rim to lower the water by around a quarter, to protect the town of Botolan below from a sudden breakout.
The mountains around Pinatubo are the ancestral land of the Aeta people, and an old Aeta story speaks of a lake and a great explosion on the mountain long before 1991. The lake lies in the municipality of Botolan, Zambales, close to the borders of Pampanga and Tarlac, about 90 km northwest of Manila.
Getting there
The usual approach is from Barangay Santa Juliana in Capas, Tarlac, by four-wheel-drive vehicle, followed by a short trek to the crater rim. Clark International Airport (CRK) is about 23 km away in a straight line.
On these lists
From the encyclopaedia
Lake Pinatubo is the summit crater lake of Mount Pinatubo formed after its climactic eruption on June 15, 1991. The lake is located in the Zambales Mountains, in Botolan, Zambales, near the boundaries of Pampanga and Tarlac provinces in the Philippines. It is about 90 km (56 mi) northwest of the capital city of Manila. While one paper by researchers from Japan suggested a depth of 600 m (2,000 ft), more detailed research suggests that 95–115 m (312–377 ft) is more accurate.
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15.13000, 120.35000per Wikidata