Case No. #1515
The Compulsion at Bandai's Explosion Crater Rim
Summary
Between 2022 and 2023, five hikers at the north wall of Mount Bandai in Fukushima — formed by the 1888 phreatic eruption — independently reported experiencing a sudden, brief compulsion to jump from the cliff edge while standing at a specific viewpoint (a zone roughly 20–30 meters in diameter). Each episode lasted 5–30 seconds and resolved without action. Volcanic research found localized elevated CO₂ and H₂S emissions at the site; infrasound measurements also showed higher readings than surrounding areas. Both factors are known to produce cognitive and sensory alterations.
Details
Mount Bandai's north wall was created by the catastrophic phreatic eruption of 1888, which killed more than 400 people. The escarpment remains volcanically active; localized gas emissions are present. Access to the north wall area is restricted due to ongoing hazard designation.
The first report, July 2022, came from a male hiker in his thirties on a guided trek. Near a north wall viewpoint, he experienced a sudden strong impulse to jump from the cliff edge. The impulse lasted 10–15 seconds then disappeared abruptly, leaving him confused and shaken. The guide told him: "I hear the same thing from a few visitors each year at this spot."
Five similar reports were filed across 2022 and 2023, all concentrated in the same 20–30 meter zone, all resolving without incident. All reporters stated they had retained consciousness throughout and had not acted on the impulse, but described the sudden onset as deeply alarming.
Volcanic researchers investigating the site confirmed localized high-concentration emissions of carbon dioxide and hydrogen sulfide from the ground — both colorless and odorless, both capable of producing impaired judgment and sensory alteration during brief exposure. Infrasound (low-frequency inaudible sound waves) measurements at the specific location showed higher values than surrounding terrain; infrasound is known from research literature to produce anxiety, disorientation, and altered perception in human subjects.
Access restrictions at the site have been strengthened; warning signage has been installed. The Bureau continues recording correlations between gas concentrations, infrasound levels, and incident reports.
Timeline
- July 2022Male hiker at north wall viewpoint experiences sudden 10–15-second compulsion to jump. Guide confirms similar reports occur several times per year.
- 2022–2023Five similar reports in the same 20–30 m zone. All resolve without incident; all reporters describe onset as alarming.
- 2022 (survey)Volcanic researcher confirms localized high-concentration CO₂ and H₂S emissions at the site.
- 2023Infrasound measurement at the site shows elevated values relative to surrounding terrain.
- 2023 onwardAccess restriction strengthened; warning signs installed. Gas/infrasound/incident correlation recording continues.
- PresentOngoing monitoring. Safety-management survey running in parallel.
Witness Testimony
Trekking participant (male, 30s)"Suddenly I had a strong urge to jump from the cliff. I was surprised at myself. It lasted ten to fifteen seconds, then was gone. I don't know where that impulse came from. Thinking about it now still frightens me."
Trekking guide (male, 40s)"I hear the same thing from a few guests at that spot every year. I didn't know why. When a specialist told me about the volcanic gas effects, I thought that might explain it."
Volcanic researcher (male, 50s)"Localized CO₂ and H₂S emissions confirmed. These can affect judgment. Infrasound is also elevated. The combination producing an impulsive sensation is a credible mechanism."
Kyu's Analysis
At a specific point, a jump impulse appears. Volcanic gas and infrasound combine there. Bandai draws people toward the edge.
