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The Valley of Ten Thousand Smokes is a valley within Katmai National Park and Preserve in Alaska which is filled with ash flow from the eruption of Novarupta on June 6–8, 1912.Following the eruption, thousands of fumaroles vented steam from the ash. Robert F. Griggs, who explored the volcano's aftermath for the National Geographic Society in 1916, gave the valley its name, saying that "the whole valley as far as the eye could reach was full of hundreds, no thousands—literally, tens of thousands—of smokes curling up from its fissured floor."
The 1912 eruption was the largest eruption by volume in the 20th century, erupting about 13 cubic kilometers of material. Novarupta generated as many as 14 major earthquakes with magnitudes between M6 and M7, a level of energy release virtually unprecedented during volcanic eruptions in modern memory, and over 100 earthquakes greater than M5. Following the eruption, the summit of Mount Katmai subsided about 1,200 meters, forming the central caldera.
Katmai is a stratovolcano, formed from alternating layers of lava flows and pyroclastic rocks. The presence of pyroclastic materials indicates that some Katmai eruptions have been explosive. The subsidence of the summit to form the central caldera and the extraordinarily energetic earthquakes accompanying the 1912 eruption are evidence of this.
The ash-filled valley covers a 40-square-mile (100 km2) area and is up to 700 feet (210 m) deep. In places deep canyons have been cut by the River Lethe, allowing observers to see the ash flow strata. Since the ash has cooled, most of the fumaroles are now extinct and despite its name the valley is no longer filled with smoke. The signs of volcanic activity are still visible on nearby hills. Katmai's most recent eruption was in 1927, but there have been non-eruptive events as recent as 2003. The Alaska Volcano Observatory still monitors Katmai's activity as part of the Katmai Cluster, where there are 5 active stratovolcanos within 15 kilometers (9 mi) of Katmai.
Following this first series of blasts, an enormous column of molten material that had lain quiescent beneath Mount Katmai apparently found access into newly created underground fissures leading to the erupting column of rhyolite beneath Novarupta. Almost as quickly as the two lavas mingled, they frothed upward and were erupted as the hybrid pumice, which chilled quickly to preserve the marbleized effect.
It is thought that the top of Mount Katmai was demolished soon after the lava flow from beneath it began. There is evidence of volcanic activity in the crater itself, however, including a small cone, recent fumarole activity, and the fact that the lake remains unfrozen in winter.
A number of explanations have been offered for the origin of the ash flow in the valley, none of them conclusive. The relatively short duration of the fumaroles, however, is explained by their origin mainly from gases sweated out of the ash as it cooled and settled. Other details remain puzzling; for example, the only remaining fumarole activity is at a place where the ash layer is relatively thin. Certain rocks and successions of ash layers also remain unaccounted for in the presently accepted sequence of events.
Plant life was slow to return to the devastated valley. Moss and algae first appeared around some of the fumaroles, but some higher plants have begun to grow on the valley floor. The valley is unable to sustain animal life, but moose and bear may cross it from time to time.
In recent years the valley has become a popular tourist attraction, reached by bus and foot from the National Park Service Lodge at Brooks River.
The 1912 eruption was the largest eruption by volume in the 20th century, erupting about 13 cubic kilometers of material. Novarupta generated as many as 14 major earthquakes with magnitudes between M6 and M7, a level of energy release virtually unprecedented during volcanic eruptions in modern memory, and over 100 earthquakes greater than M5. Following the eruption, the summit of Mount Katmai subsided about 1,200 meters, forming the central caldera.
Katmai is a stratovolcano, formed from alternating layers of lava flows and pyroclastic rocks. The presence of pyroclastic materials indicates that some Katmai eruptions have been explosive. The subsidence of the summit to form the central caldera and the extraordinarily energetic earthquakes accompanying the 1912 eruption are evidence of this.
The ash-filled valley covers a 40-square-mile (100 km2) area and is up to 700 feet (210 m) deep. In places deep canyons have been cut by the River Lethe, allowing observers to see the ash flow strata. Since the ash has cooled, most of the fumaroles are now extinct and despite its name the valley is no longer filled with smoke. The signs of volcanic activity are still visible on nearby hills. Katmai's most recent eruption was in 1927, but there have been non-eruptive events as recent as 2003. The Alaska Volcano Observatory still monitors Katmai's activity as part of the Katmai Cluster, where there are 5 active stratovolcanos within 15 kilometers (9 mi) of Katmai.
Following this first series of blasts, an enormous column of molten material that had lain quiescent beneath Mount Katmai apparently found access into newly created underground fissures leading to the erupting column of rhyolite beneath Novarupta. Almost as quickly as the two lavas mingled, they frothed upward and were erupted as the hybrid pumice, which chilled quickly to preserve the marbleized effect.
It is thought that the top of Mount Katmai was demolished soon after the lava flow from beneath it began. There is evidence of volcanic activity in the crater itself, however, including a small cone, recent fumarole activity, and the fact that the lake remains unfrozen in winter.
A number of explanations have been offered for the origin of the ash flow in the valley, none of them conclusive. The relatively short duration of the fumaroles, however, is explained by their origin mainly from gases sweated out of the ash as it cooled and settled. Other details remain puzzling; for example, the only remaining fumarole activity is at a place where the ash layer is relatively thin. Certain rocks and successions of ash layers also remain unaccounted for in the presently accepted sequence of events.
Plant life was slow to return to the devastated valley. Moss and algae first appeared around some of the fumaroles, but some higher plants have begun to grow on the valley floor. The valley is unable to sustain animal life, but moose and bear may cross it from time to time.
In recent years the valley has become a popular tourist attraction, reached by bus and foot from the National Park Service Lodge at Brooks River.
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