Global Volcanism Program | Image GVP-08280
The Laguna Río Cuarto maar occupies the northern end of a chain of volcanic vents extending to about 18 km north of Poás volcano. The 600 x 750 m wide maar has a maximum depth of 66 m and is bounded by low walls that rise only 4-20 m above the lake surface. The maar was erupted through lahar and alluvial deposits on the coastal plain at an elevation of only about 400 m above sea level.
Photo by Paul Kimberly, 1998 (Smithsonian Institution).