Earthquake lights of Matsushiro
During the Matsushiro earthquake swarm (1965–67) in Nagano, a local dentist photographed glowing domes of light over the hills, among the first photographs of earthquake lights.
1966 CE · 36.56, 138.19 · status: unexplained
The account
Tens of thousands of small quakes shook the area for two years. Dozens of witnesses described white, blue or orange glows lasting seconds to minutes, and Tsuneo Kuribayashi's photographs made the phenomenon a subject of serious study.
The sceptical view
Earthquake lights are accepted as real but their cause is debated: proposals include electric charges released from stressed rock and gas escaping from faults.
The researched reading
The best-photographed earthquake lights, recorded during a long quake swarm. A real natural phenomenon whose physics is still being worked out.
| Explanation | Weight | Why |
|---|---|---|
| A known natural phenomenon | 40% | Tsuneo Kuribayashi’s photographs and dozens of witness accounts during a two-year swarm of tens of thousands of quakes made Matsushiro the founding case for earthquake lights, which John Derr’s 1973 review established as a real geophysical effect of uncertain mechanism. |
| Undetermined | 28% | The share a generic explanation had beyond what has been shown for this case: it fits many cases like this one, but has not been demonstrated for this one. |
| Something in the surroundings | 16% | Some glows could be power lines or transformers flashing during shaking, a recognised source of false earthquake lights. |
| Perception, memory or mind | 8% | Residents watching the hills during an endless swarm would also report ordinary lights. |
| A hoax or fabrication | 3% | The photographs have been examined for decades without evidence of fakery. |
| A cultural story | 3% | Little folklore shaped these reports; they were recorded promptly. |
| Genuinely anomalous | 2% | An unexplained mechanism is not the same as something beyond physics. |
Official position: Japanese seismologists recorded the lights as part of the swarm; their cause is unresolved.