Lake Pinatubo is the summit

Summit (topography)

In topography, a summit is a point on a surface that is higher in elevation than all points immediately adjacent to it. Mathematically, a summit is a local maximum in elevation...

 crater lake

Crater lake

A crater lake is a lake that forms in a volcanic crater or caldera, such as a maar; less commonly and with lower association to the term a lake may form in an impact crater caused by a meteorite. Sometimes lakes which form inside calderas are called caldera lakes, but often this distinction is not...

 of Mount Pinatubo

Mount Pinatubo

Mount Pinatubo is an active stratovolcano located on the island of Luzon, near the tripoint of the Philippine provinces of Zambales, Tarlac, and Pampanga. It is located in the Tri-Cabusilan Mountain range separating the west coast of Luzon from the central plains, and is west of the dormant and...

 formed after its climactic eruption on June 15, 1991. The lake is located near the boundaries of Pampanga

Pampanga

Pampanga is a province of the Philippines located in the Central Luzon region. Its capital is the City of San Fernando, Pampanga. Pampanga is bordered by the provinces of Bataan and Zambales to the west, Tarlac and Nueva Ecija to the north, and Bulacan to the southeast...

, Tarlac

Tarlac

Tarlac is a landlocked province of the Philippines located in the Luzon Island. Its capital is Tarlac City. Tarlac borders Pampanga to the south, Nueva Ecija to the east, Pangasinan to the north, and Zambales to the west...

 and Zambales

Zambales

Zambales is a province of the Philippines located in the Central Luzon region. Its capital is Iba. Zambales borders Pangasinan to the north, Tarlac and Pampanga to the east, and Bataan to the south. The province lies between the South China Sea and the Zambales Mountains. With a land area of...

 provinces

Provinces of the Philippines

The Provinces of the Philippines are the primary political and administrative divisions of the Philippines. There are 80 provinces at present, further subdivided into component cities and municipalities. The National Capital Region, as well as independent cities, are autonomous from any provincial...

 in the Philippines

Philippines

The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...

 and is the deepest lake in the country at 800 m (2,624.7 ft). It is about 90 km (55.9 mi) northwest of the capital city of Manila

Manila

Manila is the capital of the Philippines. It is one of the sixteen cities forming Metro Manila.Manila is located on the eastern shores of Manila Bay and is bordered by Navotas and Caloocan to the north, Quezon City to the northeast, San Juan and Mandaluyong to the east, Makati on the southeast,...

.
Mount Pinatubo's volcanic activity has followed a cycle: centuries of repose terminated by a caldera-forming eruption with large pyroclastic flows; a post-eruption aftermath of rain-triggered lahars in surrounding drainages and dome-building that fills the caldera; and then another long quiescent period.