5:15 PM - 7:15 PM
[SVC31-P04] Interim report of creation of Land Condition Map of Volcano “Kozushima”
Keywords:land condition map of volcano (LCMV), Kozushima Island, volcanic land condition survey, volcanic landform, non-volcanic landform
1. Introduction
Geospatial Information Authority (GSI) of Japan has been providing ''Land Condition Map of Volcano (LCMV)'', which are useful for predicting volcanic disasters, planning disaster countermeasures, and conducting surveys and research. The map shows the landform classification of volcanoes based on land surface morphology, surface geology, age of formation, origin, etc. The volcanic land condition survey, which is based on literature research, landform interpretation using high-precision digital elevation model (DEM) and aerial photographs, and field surveys, is planned to be carried out over a two-year period starting in FY 2024 for developing LCMV "Kozushima''.
In this presentation, we will report on the findings through the volcanic land condition survey in Kozushima Island and the trial production.
2. Overview of LCMV
LCMV is a map that shows the landform classification of volcanoes and their surrounding areas. LCMV classifies and represents "volcanic landform" such as lava flows, pyroclastic flows, crater rims, crater walls, and debris avalanche deposits including landform caused by volcanic ejecta and "non-volcanic landform" such as erosion slopes and landslides which is caused by forces that destroy volcanic mountains.
3. Results of the trial stage of LCMV "Kozushima"
Trial production of LCMV "Kozushima" was created at a scale of 1/12,500, on A1 paper size, and covered the entire area of Kozushima Island. The islands of "Tadanaejima" and "Onbasejima", which are located around the main island were not included in the map.
The classification of volcanic landforms was mainly based on Murata et al. (2021), Isshiki (1982), and Taniguchi (1977), however, new classifications were added in the map by us.
The "Ananoyama pyroclastic cone (estimated)" was estimated to be a pyroclastic cone formed as part of the Ananoyama volcanic activity, because a northwest-facing straight slope (approximately 30 degrees inclination) and a concave that appeared to be a crater, although only a part could be seen due to it being covered by the Ananoyama lava dome.
The "Jogoyama pyroclastic cone (estimated)", 30-degree slope that spread out like a foot to the northeastern part of the Jogoyama lava dome, was estimated to be the slope of a pyroclastic cone, because the slope was approximately 400 m long and it was unlikely to be a talus slope, although no crater could be seen.
The "Chichibuyama volcanic slope" is a mountain that has the shape of a pyroclastic cone (Isshiki, 1982) , however, field surveys revealed that the Chichibuyama pyroclastic deposits were stratified from the lower to upper parts of Mt. Chichibuyama, and no pyroclastic materials that would constitute a pyroclastic cone were observed. However, since the existence of a volcanic mountain beneath the surface pyroclastic deposits could not be denied, it was classified as the "Chichibuyama volcanic slope" as "the volcanic slope covered by Chichibuyama pyroclastic deposits."
The "Tenjosan Southern Pyroclastic Cone" are located in the southwestern part of Mt. Tenjosan, with a slope length of approximately 400 m and an inclination of approximately 31 degrees, and borders the underlying Tenjosan pyroclastic flow deposit surface at the slope conversion line. Since pyroclastic materials that constitute a pyroclastic cone were observed on the field surveys, it was determined that this slope is part of a pyroclastic cone.
In addition, the distribution of the "Tenjosan pyroclastic flow deposit surface" pointed out by Isshiki (1982) was depicted in more detail.
4. Summary
A volcanic land condition survey was conducted on Kozushima Island, and a new landform classification was established based on landform interpretation and field surveys in the trial production of LCMV "Kozushima''. We will continue to examine the validity of this classification and aim to publish the map in FY 2025.
Geospatial Information Authority (GSI) of Japan has been providing ''Land Condition Map of Volcano (LCMV)'', which are useful for predicting volcanic disasters, planning disaster countermeasures, and conducting surveys and research. The map shows the landform classification of volcanoes based on land surface morphology, surface geology, age of formation, origin, etc. The volcanic land condition survey, which is based on literature research, landform interpretation using high-precision digital elevation model (DEM) and aerial photographs, and field surveys, is planned to be carried out over a two-year period starting in FY 2024 for developing LCMV "Kozushima''.
In this presentation, we will report on the findings through the volcanic land condition survey in Kozushima Island and the trial production.
2. Overview of LCMV
LCMV is a map that shows the landform classification of volcanoes and their surrounding areas. LCMV classifies and represents "volcanic landform" such as lava flows, pyroclastic flows, crater rims, crater walls, and debris avalanche deposits including landform caused by volcanic ejecta and "non-volcanic landform" such as erosion slopes and landslides which is caused by forces that destroy volcanic mountains.
3. Results of the trial stage of LCMV "Kozushima"
Trial production of LCMV "Kozushima" was created at a scale of 1/12,500, on A1 paper size, and covered the entire area of Kozushima Island. The islands of "Tadanaejima" and "Onbasejima", which are located around the main island were not included in the map.
The classification of volcanic landforms was mainly based on Murata et al. (2021), Isshiki (1982), and Taniguchi (1977), however, new classifications were added in the map by us.
The "Ananoyama pyroclastic cone (estimated)" was estimated to be a pyroclastic cone formed as part of the Ananoyama volcanic activity, because a northwest-facing straight slope (approximately 30 degrees inclination) and a concave that appeared to be a crater, although only a part could be seen due to it being covered by the Ananoyama lava dome.
The "Jogoyama pyroclastic cone (estimated)", 30-degree slope that spread out like a foot to the northeastern part of the Jogoyama lava dome, was estimated to be the slope of a pyroclastic cone, because the slope was approximately 400 m long and it was unlikely to be a talus slope, although no crater could be seen.
The "Chichibuyama volcanic slope" is a mountain that has the shape of a pyroclastic cone (Isshiki, 1982) , however, field surveys revealed that the Chichibuyama pyroclastic deposits were stratified from the lower to upper parts of Mt. Chichibuyama, and no pyroclastic materials that would constitute a pyroclastic cone were observed. However, since the existence of a volcanic mountain beneath the surface pyroclastic deposits could not be denied, it was classified as the "Chichibuyama volcanic slope" as "the volcanic slope covered by Chichibuyama pyroclastic deposits."
The "Tenjosan Southern Pyroclastic Cone" are located in the southwestern part of Mt. Tenjosan, with a slope length of approximately 400 m and an inclination of approximately 31 degrees, and borders the underlying Tenjosan pyroclastic flow deposit surface at the slope conversion line. Since pyroclastic materials that constitute a pyroclastic cone were observed on the field surveys, it was determined that this slope is part of a pyroclastic cone.
In addition, the distribution of the "Tenjosan pyroclastic flow deposit surface" pointed out by Isshiki (1982) was depicted in more detail.
4. Summary
A volcanic land condition survey was conducted on Kozushima Island, and a new landform classification was established based on landform interpretation and field surveys in the trial production of LCMV "Kozushima''. We will continue to examine the validity of this classification and aim to publish the map in FY 2025.