Laguna Caldera is a potentially active volcanic caldera and a geographical depression in Rizal,

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

. It is broadly elliptical in shape, with dimensions of 20 by 10 km. It has a summit (Mount Sembrano) elevation of . The

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...

forms the middle lobe of Laguna de Bay, bound by the Morong Peninsula and Talim Island to the west, and the Jalajala Peninsula to the east. The caldera may have formed in two stages about 1 million and 27,000-29,000 years ago, during which time at least two major

explosive eruption In volcanology, an explosive eruption is a volcanic eruption of the most violent type. A notable example is the 1980 eruption of Mount St. Helens. Such eruptions result when sufficient gas has dissolved under pressure within a Viscosity, viscous ...

s took place. It is unknown when the Laguna Caldera last erupted but it may have been active during the

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

. Deposits from the caldera form thick

ignimbrite Ignimbrite is a type of volcanic rock, consisting of hardened tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surrou ...

sheets in Rizal,

Metro Manila Metropolitan Manila ( ), commonly shortened to Metro Manila and formally the National Capital Region (NCR; ), is the capital region and largest List of metropolitan areas in the Philippines, metropolitan area of the Philippines. Located ...

, Laguna, and

Bulacan Bulacan, officially the Province of Bulacan (; ; ; ), is a Provinces of the Philippines, province in the Philippines located in the Central Luzon Regions of the Philippines, region. Its capital is the city of Malolos. Bulacan was established on ...

. Remnants of volcanic activity include undated maars at the southern end of Talim Island and a solfatara field on nearby Mount Sembrano. Given the current shape of the lake and the caldera, and how it was once connected to Manila Bay as evidenced by its ground drill geology, its formation is speculated to have been a result of an even earlier cataclysmic eruption, pointing to a possibility that it was once a volcano of considerable elevation that exploded, similar to

Krakatoa Krakatoa (), also transcribed (), is a caldera in the Sunda Strait between the islands of Java and Sumatra in the Indonesian province of Lampung. The caldera is part of a volcanic island group (Krakatoa archipelago) comprising four islands. Tw ...

Photographs

LagunaCaldera01.jpg, Laguna Caldera looking east LagunaCaldera02.jpg, Laguna Caldera looking south-east LagunaCaldera03.jpg, Laguna Caldera looking south LagunaCaldera04.jpg, Laguna Caldera looking west

References

{{DEFAULTSORT:Laguna Caldera Subduction volcanoes Volcanoes of Luzon Landforms of Laguna (province) Potentially active volcanoes of the Philippines Calderas of the Philippines Pleistocene calderas

Photographs

See also

References