The Laguna Volcanic Field (also known as the San Pablo Volcanic Field) comprises many pyroclastic cones and maars. The most prominent volcano in the field is Mount Makiling. The volcanic field lies at the southern end of Laguna de Bay on Luzon.
San Pablo City, 75th Charter Day #3606, 7 May 2015
part of a se-tenant pair
The above stamp shows Sampaloc Lake which is approximately 1.2km wide and is the youngest maar in the Laguna Volcanic Field (formed about 500–700 years ago). Maars are low-relief volcanic craters created as part of an eruption involving water and magma, older maars in the area are often filled with sediment.
Three pyrocalstic cones can also be seen in the stamp. These are from left to right Mount Lagula, Mount Nagcarlan and Mount Atimbia