The U.S. military's disaster relief mission following the massive earthquake-tsunami in Japan 10 years ago proved the value of the bilateral alliance and left a legacy of deep friendship, a then Navy commander involved in the operation said in a recent interview.

"Operation Tomodachi," named with the Japanese word for friend, was about "relearning" the strength of the alliance, former U.S. Navy 7th Fleet Commander Scott Van Buskirk recalled, referring to what became known as the largest-ever joint operation between the U.S. military and the Japanese Self-Defense Forces.

U.S. military personnel transport relief goods to a helicopter from a U.S. naval vessel on March 29, 2011 in the Pacific off the Sanriku coast, northeastern Japan. (Kyodo)

The retired vice admiral, now 64, was in Malaysia on March 11, 2011 to attend a naval event on the island of Borneo when he heard that a magnitude 9.0-quake had struck off the coast of Japan's northeastern Miyagi Prefecture.

As he watched TV footage of tsunami waters rolling across the land, he started making phone calls and forming a plan to support Japan in disaster relief and humanitarian assistance, such as by checking possible access to disaster-affected sites for vertical-lift helicopters.

Within hours, much of the fleet was on the move, repositioning ships and aircraft. But adding to the challenges was the rapidly unfolding crisis at the tsunami-hit Fukushima Daiichi nuclear power plant, which eventually suffered triple meltdowns.

"It was a crisis unheard of in terms of how do you deal with all that complexity," Van Buskirk said, also recounting the harsh winter weather conditions at that time.

From his viewpoint, the information flow between the United States and Japan over the quake and tsunami relief efforts was "very good," whereas communication regarding the nuclear crisis was "not smooth" in the beginning due partly to the difficulty of grasping the situation amid a series of hydrogen explosions at reactor buildings.

"Certainly the issue with the reactor plants was the most complex," the former commander said.

U.S. aircraft carrier Ronald Reagan, which served as a refueling base for aircraft involved in rescue and recovery operations, at one point had to be positioned farther offshore to avoid any possible radiation contamination.

Nonetheless, drones and planes with sensors were used to monitor the situation at the Fukushima plant, Van Buskirk said, calling it "a very positive thing."

Another key challenge was to assist the reopening of the debris-covered Sendai airport in Miyagi Prefecture and ports to allow more supplies to flow to the devastated areas, he said. A U.S. salvage ship helped to do the work along with U.S. troops.

Screenshot image shows former U.S. Navy 7th Fleet Commander Scott Van Buskirk giving an online interview in February 2021. (Kyodo) 

At the peak of Operation Tomodachi, joined by all the U.S. military services, the United States had 24,000 personnel, 189 aircraft and 24 Navy ships supporting humanitarian assistance and disaster relief efforts, according to a 2011 report by the Congressional Research Service. Most activities ended in April that year.

The U.S. 7th Fleet is the Navy's largest forward-deployed fleet, with an area of responsibility stretching from the Western Pacific to the Indian Ocean. It is based in Yokosuka, south of Tokyo.

Looking back, Van Buskirk said he was "proud to have been there" to support the Japanese people as well as the Americans living in the country and to have "the best possible outcome for something that was very, very tragic."

The overall success of Operation Tomodachi was facilitated through years of joint exercises and trusted personal relationships, such as Van Buskirk recalled having with then Japanese Self-Defense Fleet Commander-in-Chief Kenichi Kuramoto.

"In time of crisis, you want to be able to pick up the phone and call your good friend...'Ken-san, where do you need help?' 'What can we do for you?' or he could call me," he said, adding that such "valuable" things "cannot be taken for granted."

"So my point is, you need to invest in those things, continue to invest in exercises," including those to prepare for humanitarian assistance and those conducted among the so-called Quad involving the United States, Japan, Australia and India, Van Buskirk said.

He also said "there's never been a better name" than Tomodachi to describe the operation. "This was two friends, working together...and doing something that was beyond the military, beyond anything else, it was to support the people."

"What I've been touched by is the legacy of that still has continued and should continue to be celebrated," he added.