14:45 〜 15:00
[HTT18-05] 八幡平後生掛地熱地域での自然電位分布の変遷
キーワード：自然電位、地熱地帯、後生掛温泉、十和田八幡平国立公園
We have visited the Goshogake geothermal area behind the Goshogake hot spring for several years and carried out geophysical explorations including GPR (Ground Penetrating Radar), ERT (Electric Resistivity Tomography), SP (self-potential) and electromagnetic induction method using GEM-2 and so on in order to investigate the subsurface hydrothermal structure.
Goshogake geothermal area is on the foot of the Akita-Yakeyama volcano and the site is in the Towada-Hachimantai National Park, northeast of Japan. We can observe the geothermal activities like as fumaroles, mud pots and hot springs at the site. Recent years the geothermal activity has destroyed the walkway named Nature study route of Goshogake spa maintained by the Nature Conservation Division of Akita prefecture. The walkway is partly off limits and under construction of the new route.
We conducted SP measurements at the Goshogake geothermal area along the walkway totally 8 times from 2019 to 2023. Copper-copper sulfate electrode, one of non-polarized electrode are used and the potential data were acquired at around every 30 m. The locations are recorded by a handy GPS (Garmin etrex 30, etc.).
We have found the positive anomalies of SP are in accordance with the geological alteration zones. In addition, we can recognize the positive anomalies around Oname-Motome hot spring and Oyu-numa hot pond and negative anomaly around Odoro-Kazan. The sources of the anomalies are around 1000 m in depth inferred by the equivalent source model. We can see the time lapse change of SP distribution in the Goshogake geothermal area including perhaps seasonal changes, for example in attached figure. We try to explain of the components of the change with the numerical models.
Goshogake geothermal area is on the foot of the Akita-Yakeyama volcano and the site is in the Towada-Hachimantai National Park, northeast of Japan. We can observe the geothermal activities like as fumaroles, mud pots and hot springs at the site. Recent years the geothermal activity has destroyed the walkway named Nature study route of Goshogake spa maintained by the Nature Conservation Division of Akita prefecture. The walkway is partly off limits and under construction of the new route.
We conducted SP measurements at the Goshogake geothermal area along the walkway totally 8 times from 2019 to 2023. Copper-copper sulfate electrode, one of non-polarized electrode are used and the potential data were acquired at around every 30 m. The locations are recorded by a handy GPS (Garmin etrex 30, etc.).
We have found the positive anomalies of SP are in accordance with the geological alteration zones. In addition, we can recognize the positive anomalies around Oname-Motome hot spring and Oyu-numa hot pond and negative anomaly around Odoro-Kazan. The sources of the anomalies are around 1000 m in depth inferred by the equivalent source model. We can see the time lapse change of SP distribution in the Goshogake geothermal area including perhaps seasonal changes, for example in attached figure. We try to explain of the components of the change with the numerical models.