‘TSUNAMI FIRES’: Experts uncovered bizarre reason behind post-earthquake phenomenon

The 1993 Hokkaido earthquake occurred at 13:17pm on 12 July 1993 in the Sea of Japan, near the island of Hokkaido. It had a magnitude of 7.7 and at the time, was the strongest quake to strike Japan in 25 years. Rescue workers at the time confirmed 97 people were killed, while 190 people were injured and more than 160 people missing.

The New York Times reported how the disaster produced “scenes of utter devastation, with houses and Buddhist temples splintered in the mud, boats thrown far inland, and roofs of some homes floating out to sea”.

But the mystery of ships spontaneously bursting into flames following the tsunami crashing into the harbour- with winds from the tsunami driving the blaze further inland has never been solved.

As a second tsunami wave hurtled toward shore, it generated powerful winds that pushed the burning boats to the coastal area, spreading the fire into the city.

But now, researchers and experts in Japan have claimed that a build-up methane gas on the floor of the Sea of Japan were disturbed by the earthquake was a likely cause of the fires that swept through the area.

Using previously “inaccessible” footage from Japanese broadcaster NHK, Yuji Enomoto, a professor emeritus at Shinshu University in Japan, explained how witnesses at the time described rising mists and seawater “foaming” before the fires took place.

One witness said: “The offshore area looked shining white and bubbling.”

Researchers from the university say the bubbles that witnesses described seeing in 1993 represented methane that was formerly embedded in the seafloor, but was dislodged by the ground sliding.

The once-trapped methane bubbles were then squeezed up and out into the air by the tsunami front, which transported them to the shore.

The report said: “Bacterial mats suggesting methane release have been found off the west of Okushiri Island, where the tsunami originated.”

The researchers held tests that found when electrostatic energy generated a charge of 0.28 millijoules, the methane would catch fire.

The team concluded that methane electrostatically ignited when the wind violently drove released methane into Aonae Harbor’s quay.

Methane bubbles that had accumulated on the decks of the fishing boats sparked.

The fire spread further when it reached oil or petrol leaking from a car that had been swept into the harbour.

Professor Enomoto told Live Science that tsunami fires are an “understudied hazard” – and pointed out significant quantities of methane remain buried in coastal regions of Japan.

The North Japanese island of Hokkaido was once again rocked by an earthquake on Septmber 6 of this year.

As of September 12, around 1,600 people were living in evacuation centers in the affected areas, including the city of Atsuma.