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 structural integrity of such a chamber, greatly diminishing its capacity to support its own roof, and any substrate or rock resting above. The ground surface then collapses into the emptied or partially emptied magma chamber, leaving a large depression at the surface. Although sometimes described as a crater, the feature is actually a type of sinkhole, as it is formed through subsidence and collapse rather than an explosion or impact. Compared to the thousands of volcanic eruptions that occur over the course of a century, the formation of a caldera is a rare event, occurring only a few times within a given window of 100 years. Only eight caldera-forming collapses are known to have occurred between 1911 and 2018, with a caldera collapse at Kīlauea, Hawaii in 2018. Volcanoes that have formed a caldera are sometimes described as "caldera volcanoes".
Lake Toba is a large natural lake in North Sumatra, Indonesia, occupying the caldera of the Toba supervolcano. The lake is located in the middle of the northern part of the island of Sumatra, with a surface elevation of about 900 metres (2,953 ft), the lake stretches from 2.88°N 98.52°E to 2.35°N 99.1°E. The lake is about 100 kilometres long, 30 kilometres (19 mi) wide, and up to 505 metres (1,657 ft) deep. It is the largest lake in Indonesia and the largest volcanic lake in the world. Toba Caldera is one of twenty geoparks in Indonesia, and was recognised in July 2020 as one of the UNESCO Global Geoparks.
A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
Sand Lake is a town in south-central part of Rensselaer County, New York, United States. Sand Lake is about 13 miles east of Albany, New York. As of the 2020 census, the population was 8,348. Within the town are four hamlets: West Sand Lake, Averill Park, Glass Lake and the hamlet of Sand Lake. Its four lakes are a source of recreation. Many commercial enterprises of the 19th century and into the 20th century relied on power generated from the Wynants Kill Creek and Burden Lake mills. The area is known for its fertile soil for grazing and agriculture.
The Ring of Fire is a tectonic belt of volcanoes and earthquakes.
Kīlauea is an active shield volcano in the Hawaiian Islands. It is located along the southeastern shore of Hawaii Island. The volcano is between 210,000 and 280,000 years old and grew above sea level about 100,000 years ago. Since the islands were settled, it has been the most active of the five volcanoes that together form the island and among the most active volcanoes on Earth. The most recent eruption began in December 2024.
The San Francisco volcanic field is an area of volcanoes in northern Arizona, north of Flagstaff, US. The field covers 1,800 square miles (4,700 km2) of the southern boundary of the Colorado Plateau. The field contains 600 volcanoes ranging in age from nearly 6 million years old to less than 1,000 years, of which Sunset Crater is the youngest. The highest peak in the field is Humphreys Peak, at Flagstaff's northern perimeter: the peak is Arizona's highest at 12,633 feet and is a part of the San Francisco Peaks, an active stratovolcano complex.
An active volcano is a volcano that has erupted during the Holocene, is currently erupting, or has the potential to erupt in the future. A volcano that is not currently erupting but could erupt in the future is known as a dormant volcano. Volcanoes that will not erupt again are known as extinct volcanoes.
Pagan is a volcanic island in the Marianas archipelago in the northwest Pacific Ocean, under the jurisdiction of the Commonwealth of the Northern Mariana Islands. It lies midway between Alamagan to the south and Agrihan to the north. The island has been largely uninhabited since the majority of the residents were evacuated due to volcanic eruptions in 1981.
Lava lakes are large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression. The term is used to describe both lava lakes that are wholly or partly molten and those that are solidified.
The Albuquerque volcanic field is a monogenetic volcanic field in the Albuquerque Basin in New Mexico, United States. It is located about 7 miles (11 km) west of the city of Albuquerque, and is contained within the borders of Petroglyph National Monument. The field was active from 190,000 to 155,000 years ago and includes lava flows, cinder cones, and spatter cones. The oldest lava flows cover about 23 square miles (60 km2). The cones are aligned and possibly formed above two roughly north-south trending fissures. Vulcan is the highest feature. Its base is made of cinder, but the crater contains a lava dome that was cut by an explosive eruption.
A lake island is any landmass within a lake. It is a type of inland island. Lake islands may form a lake archipelago.
Mount Dana is a small stratovolcano of the Alaska Peninsula, United States, located northeast of Canoe Bay inlet at the head of Pavlof Bay. It was the source for a major eruption about 3840 years ago that produced a pyroclastic flow that filled valleys south and west of the volcano's crater and reached the sea at Canoe Bay.
Siskiwit Lake is the largest lake on Isle Royale in Lake Superior. 4,150 acres (16.8 km2) in area, the lake has cold, clear water which is relatively low in nutrients. Tributaries include the Little Siskiwit River, and the lake's outlet is the Siskiwit River which flows into Lake Superior.
A volcanic crater lake is a lake in a crater that was formed by explosive activity or a collapse during a volcanic eruption.
