Presentation Information
[O05-P05]Legends related to the Mt. Bandai debris avalanche and a geotour around the legendary sites★Invited Papers
*Yojiro Taketani1, Taro Suzuki2, Makoto Hasuoka1 (1.Bandaisan Geopark Council, 2.Asia Air Survey Co., Ltd)
Keywords:
Mt. Bandai,debris avalanche,legend,geotour
Introduction
Mt. Bandai, an active volcano located in the southern Ou mountains, have created unique topography and unusual rock formations caused by debris avalanches due to mountain collapses, and some legends surrounding them remain. The legends may contain information about past volcanic activity. We interpreted these legends from a geological perspective.
1. Legends related to debris avalanches and their geological perspective
(1) Okinajima debris Avalanche (approximately 50,000 years ago)
Okinajima island: An only island in Lake Inawashiro, located south of Mt. Bandai.
An old story: Mt. Bandai erupted, and the floodwaters submerged the village at the bottom of Lake Inawashiro except around a kind-hearted girl Okina’s house.
Geological perspective: Lake Inawashiro was created 50,000 years ago when the Okinajima debris avalanche caused by the eruption of Mt. Bandai dammed a river. The debris avalanche formed many small hills called Nagareyama (flow mound) at the foot of the mountain. Okinajima is one of these flow mounds.
Gennoishi rock: A big rock along a roadway in the early modern period.
A legend: When Genno, a Buddhism priest in the Nanboku-cho period, admonished the killing stone in the Nasu area. Most of the rock broke into pieces with his roar, but one of the pieces flew to the land of Aizu. Genno further split the rock to prevent any further trouble.
Geological perspective: Gennoishi was not blown in, but rather a rock carried by the aforementioned Okinajima debris avalanche.
(2) Biwazawa debris avalanche (approximately 2,500 years ago)
Nekoishi rocks: Two huge rocks along Nagase River, flowing on the east side of Mt. Bandai
An old story: When Mt. Bandai erupted, a couple of cats fled down the mountain and came to Nagase River. The male cat managed to cross the river, but the female cat was never able to make it across. The female cat turned into a rock, and the male cat never missed visiting his wife's cat rock.
Geological perspective: Nekoishi is two huge rocks of volcanic breccia that were carried by the Biwazawa debris avalanche due to the eruption of Mt. Bandai approximately 2,500 years ago.
(3) Debris avalanche (Nara to early Heian Period)?
Enichiji Temple: An ancient temple located at the southwestern foot of Mt. Bandai.
A legend: Demons inhabited in Mt. Bandai constantly cursed and harmed agricultural work. In 806, Mt. Bandai rampaged and formed a large lake. In 807, a famous Buddhism priest Kukai came to this area and practiced secret teachings. As a result the demons then fled to another peak.
Geological perspective: It is doubtful whether Mt. Bandai rampaged and formed a large lake in 806. However, wood fragments dating from Nara to early Heian Period have been found in the gravel layer on the eastern foot of Mt. Bandai, suggesting that a small lake may have been created during this period following a partial collapse of Mt. Bandai.
2. Significance of the legends
Around Mt. Bandai there are many legends related to Mt. Bandai's eruptions, indicating that residents were strongly aware of Mt. Bandai as an active volcano. However, in order to link the legends to Mt. Bandai's past volcanic activity, a reasonable and convincing explanation is necessary. Rather, we believe it is important through the legends to understand the views on nature, religion, and morality of the people who have coexisted with the volcano for many years.
3. Utilization the legends in Geoparks
In May 2025, a geotour was held at the Bandaisan Geopark on the Geology Day, visiting sites associated with the legends of the Mt. Bandai debris avalanche and explaining their geological background. At the same time, the Red Relief Image Map around Mt. Bandai was used to verify its effectiveness in understanding the volcanic topography and its cause. Geopark outreach activities focused on the legends will contribute to reaffirming the relationship between volcanoes and humans, and enhancing the region's identity.
Mt. Bandai, an active volcano located in the southern Ou mountains, have created unique topography and unusual rock formations caused by debris avalanches due to mountain collapses, and some legends surrounding them remain. The legends may contain information about past volcanic activity. We interpreted these legends from a geological perspective.
1. Legends related to debris avalanches and their geological perspective
(1) Okinajima debris Avalanche (approximately 50,000 years ago)
Okinajima island: An only island in Lake Inawashiro, located south of Mt. Bandai.
An old story: Mt. Bandai erupted, and the floodwaters submerged the village at the bottom of Lake Inawashiro except around a kind-hearted girl Okina’s house.
Geological perspective: Lake Inawashiro was created 50,000 years ago when the Okinajima debris avalanche caused by the eruption of Mt. Bandai dammed a river. The debris avalanche formed many small hills called Nagareyama (flow mound) at the foot of the mountain. Okinajima is one of these flow mounds.
Gennoishi rock: A big rock along a roadway in the early modern period.
A legend: When Genno, a Buddhism priest in the Nanboku-cho period, admonished the killing stone in the Nasu area. Most of the rock broke into pieces with his roar, but one of the pieces flew to the land of Aizu. Genno further split the rock to prevent any further trouble.
Geological perspective: Gennoishi was not blown in, but rather a rock carried by the aforementioned Okinajima debris avalanche.
(2) Biwazawa debris avalanche (approximately 2,500 years ago)
Nekoishi rocks: Two huge rocks along Nagase River, flowing on the east side of Mt. Bandai
An old story: When Mt. Bandai erupted, a couple of cats fled down the mountain and came to Nagase River. The male cat managed to cross the river, but the female cat was never able to make it across. The female cat turned into a rock, and the male cat never missed visiting his wife's cat rock.
Geological perspective: Nekoishi is two huge rocks of volcanic breccia that were carried by the Biwazawa debris avalanche due to the eruption of Mt. Bandai approximately 2,500 years ago.
(3) Debris avalanche (Nara to early Heian Period)?
Enichiji Temple: An ancient temple located at the southwestern foot of Mt. Bandai.
A legend: Demons inhabited in Mt. Bandai constantly cursed and harmed agricultural work. In 806, Mt. Bandai rampaged and formed a large lake. In 807, a famous Buddhism priest Kukai came to this area and practiced secret teachings. As a result the demons then fled to another peak.
Geological perspective: It is doubtful whether Mt. Bandai rampaged and formed a large lake in 806. However, wood fragments dating from Nara to early Heian Period have been found in the gravel layer on the eastern foot of Mt. Bandai, suggesting that a small lake may have been created during this period following a partial collapse of Mt. Bandai.
2. Significance of the legends
Around Mt. Bandai there are many legends related to Mt. Bandai's eruptions, indicating that residents were strongly aware of Mt. Bandai as an active volcano. However, in order to link the legends to Mt. Bandai's past volcanic activity, a reasonable and convincing explanation is necessary. Rather, we believe it is important through the legends to understand the views on nature, religion, and morality of the people who have coexisted with the volcano for many years.
3. Utilization the legends in Geoparks
In May 2025, a geotour was held at the Bandaisan Geopark on the Geology Day, visiting sites associated with the legends of the Mt. Bandai debris avalanche and explaining their geological background. At the same time, the Red Relief Image Map around Mt. Bandai was used to verify its effectiveness in understanding the volcanic topography and its cause. Geopark outreach activities focused on the legends will contribute to reaffirming the relationship between volcanoes and humans, and enhancing the region's identity.