Laguna Caldera is a potentially active

volcanic caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

and a geographical depression in

Rizal Rizal, officially the Province of Rizal ( fil, Lalawigan ng Rizal), is a Provinces of the Philippines, province in the Philippines located in the Calabarzon region in Luzon. Its capital is the city of Antipolo. It is about east of Manila. The p ...

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

. It is broadly elliptical in shape, with dimensions of 20 by 10 km. It has a summit elevation of 743 m or 2,438 feet. The

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

forms the middle lobe of

Laguna de Bay Laguna de Bay (Spanish language, Spanish for "Lagoon/Lake of Bay, Laguna, Bay"; tl, Lawa ng Bay, ), also known as Laguna Lake, is the List of lakes of the Philippines, largest lake in the Philippines. It is located southeast of Metro Manila, b ...

, bound by the Morong Peninsula and

Talim Island Talim Island is the largest lake island in Laguna de Bay, the largest lake in the Philippines. The hilly island is within the boundaries of the Province of Rizal, under the jurisdiction of two municipalities. The western side is part of the munic ...

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 viscous magma such ...

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 geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

. 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 (often shortened as Metro Manila; fil, Kalakhang Maynila), officially the National Capital Region (NCR; fil, link=no, Pambansang Punong Rehiyon), is the capital region, seat of government and one of three List of metrop ...

Laguna Laguna (Italian and Spanish for lagoon) may refer to: People * Abe Laguna (born 1992), American DJ known as Ookay * Andrés Laguna (1499–1559), Spanish physician, pharmacologist, and botanist * Ana Laguna (born 1955), Spanish-Swedish ballet d ...

, and

Bulacan Bulacan, officially the Province of Bulacan ( tl, Lalawigan ng Bulacan), is a province in the Philippines located in the Central Luzon region. Its capital is the city of Malolos. Bulacan was established on August 15, 1578, and part of the Metr ...

. Remnants of volcanic activity include undated

maar A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow ...

s at the southern end of Talim Island and a

solfatara A fumarole (or fumerole) is a vent in the surface of the Earth or other rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcani ...

field on nearby

Mount Sembrano Mount Sembrano is a volcano located between Rizal and Laguna of the Calabarzon region in the Philippines. Mt. Sembrano is situated about east by road from the capital city of Manila. Geography Mount Sembrano lies between the boundaries of th ...

. 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.

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) Calderas of the Philippines Pleistocene calderas

Photographs

See also

References