How can you warn divers of incoming tsunami? Japan agencies, orgs have no answer

FUKUOKA — How would you know if a tsunami warning had been issued while you were diving? The Japan Coast Guard (JCG) nor any agency or organization in the marine recreation industry currently has a solution.

The earthquake in Taiwan on April 3, which triggered a tsunami warning in wide areas of Okinawa Prefecture, spotlighted these concerns. Although the tsunami measuring 0.3 meters on the islands of Yonaguni and Miyako and 0.2 meters on Ishigaki Island did not hurt anyone, concerned parties are struggling with how to warn divers of the danger while they are in the water, as tourists visit from all over Japan to enjoy the beauty of the island prefecture’s waters.

The tsunami warning was issued for Okinawa’s main island region and the Miyako and Yaeyama island region at around 9 a.m. on April 3. Akinori Anno, 60, left the seafront dive shop in Yomitan, Okinawa Prefecture, he has been running for more than 30 years and headed for nearby high ground. He happened to have no reservations that day, but he imagined what it would be like if a warning had been issued while customers were in the water, and worried they might not reach safety if a tsunami hit immediately.

Generally, when a boat captain wants the divers back due to a sudden change in weather conditions, they repeatedly rev the boat’s engine or tap the ladder into the water as an aural signal. However, the captain may also be the underwater guide, and may not always be aware of a tsunami warning. There is also radio equipment that transmits warnings to divers, but it is expensive and not widely used.

Yukio Murata, 71, the head of a volunteer organization that has been working on diving safety in Okinawa Prefecture, said, “We send emergency signs from the surface by revving the engine in many cases, but I feel uneasy when I’m diving as a guide. All I can hope for is that I’ll notice something’s off by feeling the tremors or hearing the ground shake.”

Since the 2011 Great East Japan Earthquake, which caused massive tsunami damage, interest in tsunami countermeasures has increased among diving professionals, but no fundamental measures have been found.

What would happen if one was caught in a tsunami while diving?

According to Koji Miura, a professor of physical fitness science at International Pacific University who teaches diving, divers may be swept ashore by a tsunami and become trapped in drifting debris or drowned by the ocean current. On the other hand, he pointed out that “it will be important for guides to be aware of changes in the water after the earthquake” since there is no established means of communicating warnings. “It’s important to check in advance how to respond to emergencies, such as how to evacuate,” he said.

The JCG also calls for general safety measures for diving, but apparently has no specific tsunami response measures for divers. It seems that further tsunami countermeasures will be required to truly enjoy the beautiful sea.

(Japanese original by Toru Morinaga, Kyushu News Department)