Aniakchak National Monument and Preserve is a U.S. National Monument and National Preserve, consisting of the region around the Aniakchak volcano on the Aleutian Range of south-western Alaska. It has erupted at least 40 times over the last 10,000 years. The monument is one of the least-visited places in the National Park System due to its remote location and difficult weather. The area was proclaimed a National Monument on December 1, 1978, and established as a National Monument and Preserve on December 2, 1980. The National Monument encompasses and the preserve . Visitation to Aniakchak is the lowest of all areas of the U.S. National Park System, according to the NPS, with only 100 documented recreational visits in 2017. Most visitors fly into Surprise Lake inside Aniakchak Crater, but the frequent fog and other adverse weather conditions make landing in the lake difficult. It is also possible to fly into the nearby village of Port Heiden and proceed overland to the Aniakchak Crater.
The core of the national monument lands encompasses the wide Aniakchak Crater. The high point on the caldera rim is Aniakchak Peak. The lake within the caldera, Surprise Lake, is the source of the Aniakchak River. Multiple streams and rivers within the caldera flow into Surprise Lake to form it. In addition to Surprise Lake, the other prominent feature inside the caldera is Vent Mountain, the site of the most recent (1931) eruption within the caldera. The preserve lands flank the monument on either side. Subsistence hunting is allowed in both the monument and preserve, and sport hunting is allowed in the preserve. The region was virtually unexplored until the 1920s, when exploration for oil brought reports of an un-described volcano. A moderate eruption in 1931 forming Vent Mountain resulted in significant publicity, spurring studies to declare the region a national monument. It was not until 1978 that a monument was proclaimed by President Jimmy Carter under the Antiquities Act. The monument and preserve were established within their final boundaries in 1980 with the passage of the Alaska National Interest Lands Conservation Act.
Description Aniakchak National Monument and Preserve is located about southwest of Anchorage, Alaska, on the Alaska Peninsula. It is not accessible by road, except from Port Heiden, a nearby village, and then only to the outer flanks of the caldera. The only ways to reach the monument are by floatplane to lakes, particularly Surprise Lake, or sheltered coastal waters, or by boat or airplane to coastal towns near preserve lands followed by overland or overwater traverse. Notoriously bad weather makes access to Aniakchak unpredictable. Drop-offs and pick-ups may be significantly delayed. There are no permanent facilities in the monument and the NPS does not require visitor registration. Visitor services are provided by the interagency King Salmon Visitor Center in King Salmon, Alaska, shared with Lake Clark National Park, Katmai National Park and Preserve, and other National Park Service and U.S. Fish and Wildlife Service units and Alaska local and state agencies. The monument adjoins the Alaska Peninsula National Wildlife Refuge on its northeast and southwest sides. Monument lands amount to , and preserve lands .
The national monument is centered on the diameter crater of ancient Mount Aniakchak, which was destroyed and the resulting crater formed during a caldera collapse event about 3,700 years ago. The original mountain, about tall, collapsed into its magma chamber, leaving an approximate deep summit crater. (The elevation of the high point on the crater rim, Aniakchak Peak, is approximately 4,380 feet. The elevation of the low point of the caldera floor, at the mouth of Surprise Lake and the beginning of the Aniakchak River, is approximately 1,055 feet.) The monument and surrounding preserve include the volcanic feature, the wild Aniakchak River, the Bristol Bay coastal habitat, and portions of the coast of the Pacific Ocean.
Prominent features within Aniakchak crater include Surprise Lake and the Gates (the cleft in the caldera rim through which the Aniakchak River flows from Surprise lake to the Pacific Ocean) and Vent Mountain.
The Aniakchak River flows 30 miles to Aniakchak Bay on the coast and can be navigated by inflatable raft or kayak. Upper stretches of the river drop as much as 75 feet per mile and narrow to as little as 15 feet. Lower sections widen into meandering oxbows at sections within view of Cape Horn.
Geology The monument and preserve include four major physiographic regions. The monument is centered on the mountains of the Aleutian Range and Aniakchak Crater. The volcano's caldera presents an active volcanic and geothermal landscape and Surprise Lake, the source of the Aniakchak River. Extending outward from the mountains are the glacially altered river valleys. The coastline region extends for along the southeastern side of the peninsula where it faces the Pacific Ocean.
The mountain spine of the Aleutian Range consists of uplifted mountains of moderate height, reaching . The mountain environment is predominantly alpine tundra. Superimposed on the mountain chain are a series of volcanoes, the largest of which is the remnant of Mount Aniakchak, now largely collapsed into its caldera, the floor of which lies about above sea level. The caldera was once partly filled by a crater lake that covered about 50% of the crater. The caldera wall was eventually breached, leading to a catastrophic flood as the lake drained. Its remnant is Surprise Lake, the source of the Aniakchak River.
The river valley zones are subdivided into southeastern and northwestern areas. On the southeast side, the rivers fall steeply through volcanic ash deposits where vegetation has largely recolonized the areas devastated by the volcano's eruption. On the northwest side, the rivers are more gently sloped and the land is boggy with lush vegetation. The southeast coastal region is deeply indented, with coastal cliffs, headlands and islands. Three large bays are the remnants of earlier volcanic craters. The two larger bays are Aniakchak and Amber Bays, and the smaller is Kejulik Bay. All have cinder-covered beaches between the sea and large freshwater lagoons.
Ecology The Alaska Peninsula climate is cool and wet. Regular Pacific Ocean storms produce estimated annual precipitation exceeding along the coast, with more precipitation probable in the mountains. The weather is typically cloudy and windy, producing low ceilings and rough waters that make both aviation and boating hazardous.Norris, Ch. 13
Encompassing coastal and mountain habitats, Aniakchak is home to a wide variety of plants and animals. Large terrestrial animals include caribou, Alaskan moose, brown bears, wolf packs and wolverines. Marine mammals include harbor seals, sea lions and sea otters. The 1931 volcanic eruption at Vent Mountain within the crater disrupted plant communities around the volcano, which are now recovering and which are the subject of scientific research.
History The prehistory of the Aniakchak area is only beginning to come to light as a result of recent archaeological surveys funded by the National Park Service. Present-day native residents consider themselves to be of Aleut ancestry, but linguistic studies indicate that they are related to the similarly named Alutiiq people of Peninsula Yup'ik ancestry. Currently, there is no evidence to suggest when Alutiiq-speaking people first arrived in the region. Archaeological data reveal that the entire central Alaska Peninsula was occupied, abandoned, and re-colonized numerous times, perhaps in response to recurrent catastrophic volcanism and subsequent processes of ecological succession. Nothing is known of the people who lived in the area prior to the 3,700 BP eruption of the Aniakchak volcano. Because there is ample evidence for human habitation in areas nearby, prior to the caldera-forming eruption, it is unlikely that the Aniakchak region was uninhabited. However, the eruption fundamentally altered the landscape, and likely buried the pre-eruption evidence for human activity under many meters of volcanic debris. Lands nearest the caldera were largely uninhabited for millennia: the Pacific Coast was re-colonized by approximately 2000 years ago while the Meshik River drainage was re-colonized approximately 1700 years ago. The cultural affiliations of these colonists have not yet been determined, however it is likely that different people moved into the area at different times.
Russian exploration of Alaska began in the mid-18th century, with fur traders arriving shortly afterwards to take advantage of the sea otters that populated the coast. Traders and native trappers took sea otters along both sides of the Aleutian peninsula. The first recorded mention of the Aniachak region appears in an 1827 atlas, which notes "Baie Amah-chak" and "Cap Kumlik". In 1831 the coast was mapped by the Russian Navy and followed up by two more expeditions in the 1840s. The region was mostly avoided through the rest of the 19th century, apart from a few fur trappers who did not prosper.
The development of the salmon fishing industry in Alaska brought a cannery to Chignik Lagoon in 1882, about southwest of the future monument. The industry expanded, building fish traps in Aniakchak Bay by 1917. Other traps followed through 1937, some operating until 1949. The Alaska Packers' Association built a bunkhouse on Aniakchak Bay in the 1920s to house workers who maintained the trap and harvested fish during the summer months. At the same time, fur trappers arrived, this time to gather furs from inland mammals.
Reports of oil seeps on the peninsula and on the cape between Aniakchak and Amber Bays in the 1920s brought petroleum exploration and claims, some of which described the "Aniakchak Field". Detailed surveys established that the seeps did not exist, and that much of the region was composed of non-oil-bearing igneous rock, ending speculation. The reports did provoke interest from the U.S. Geological Survey, and in 1922 and 1925 USGS parties surveyed the region. These surveys brought the first detailed accounts of what they described as an "extinct volcano", of which fragmentary information had only emerged after 1919. However, in 1931 Half Cone, one of the cinder cones in the caldera, erupted throughout May of that year, causing ashfalls at distances up to .