Yet new flaws have emerged in Defense Ministry plans to deploy the U.S.-made Aegis Ashore missile defense system in northern Japan.

Defense Minister Takeshi Iwaya admitted at a June 14 news conference that the proposed site in Akita Prefecture is at risk of being inundated by tsunami.

The disclosure, the latest in a string of errors on the planned deployment, raises new questions over the ministry's decision to spend 134 billion yen ($1.24 billion) on the system, each of two units Japan will introduce.

When it selected the Ground Self-Defense Force Araya exercise area in the prefectural capital of Akita for the defense system, no mention was made of the need for anti-tsunami measures.

But in his about-face on June 14, Iwata said that some areas of the GSDF site should be reinforced against a possible tsunami.

“Most of the training area is unlikely to be submerged by tsunami,” Iwaya said, referring to a prefectural government assessment of the tsunami danger. However, he said the western section close to the training site boundary is included in a hazard map drawn up by prefectural authorities.

He said the ministry still believes that in eastern Japan, the Araya site is best suited to station the missile defense system to protect Japan from North Korean missiles.

Japan decided to purchase the two Aegis Ashore systems in 2017 following 40 missile launches by North Korea since the previous year.

The purchase was also spurred by U.S. President Donald Trump’s “buy American” campaign. Japan planned to start operating the Aegis Ashore from fiscal 2023.

But given the recent warming of relations between Pyongyang and Washington, criticism has arisen in Japan about the wisdom of the huge defense expenditure.

The government announced in June last year that Araya and the GSDF’s Mutsumi exercise area in Yamaguchi Prefecture, western Japan, are candidates for the deployment.

But residents near the sites expressed concerns about possible health hazards from radar pulses as well as being in the field of fire if North Korea decided to retaliate with a missile attack over the deployment.

Earlier, ministry officials explained that Araya is the most suitable of all the candidate sites in eastern Japan, noting that it covers more than 1 square kilometer, is flat and located on the Sea of Japan side rather than near the Pacific coast.

To convince skeptics, it examined 19 alternative sites in Aomori, Akita and Yamagata prefectures. Five criteria to determine suitability included whether tall mountains exist nearby that could block radar pulses, the stability of electricity and water supplies and vulnerability to tsunami.

The report assessing the tsunami risk to Araya and the other 19 sites, said four would be significantly affected and another four less so.

The report made no mention of the Araya site being in danger of swamped by tsunami.

The ministry report went on to state that it did not anticipate any impact from tsunami there, which led to its decision to pick Araya from the 20 prospective sites. It also cited other considerations.

But on June 14, the Defense Ministry said the area where it planned to install the Aegis Ashore’s radar system and missile launchers fell in a section that prefectural officials predicted was at risk of being inundated by tsunami of between 2 and 5 meters.

Iwaya said the entire system would be safe if the risk area was elevated.

But the study report did not mention the need for such steps.

“I suspect ministry officials did not refer to the risk of tsunami in the report on the assumption that the impact of such could be averted if work was undertaken to elevate the land,” Iwaya said.

Earlier this month, the ministry also acknowledged another flaw in the report, which cited elevation angles of mountain peaks that were larger than the actual figures for the nine candidate sites that were ruled out.

For example, the actual elevation angle of a mountain peak at the site in Oga, Akita Prefecture, was 4 degrees. But it was listed as 15 degrees in the ministry’s report.

According to the ministry, officials who drew up the report produced a cross-section diagram using the virtual globe in the Google Earth Pro app.

But they did not realize that the diagram created was exaggerated vertically to highlight the undulation of the mountains.

When officials double checked the result with a protractor, the angles of elevation were larger than they actually are because of errors created in the original diagrams.

Anger among Akita residents was further fueled when a Defense Ministry official dozed off at June 8 session on the report.

Ministry officials are concerned that further errors by the ministry could derail the deployment.

In an effort at damage control, Iwaya will travel to Akita on June 17 to apologize to Akita Governor Norihisa Satake in person as well as other local officials.

Satake told the prefectural assembly on June 10 that the deployment had returned to the drawing board.

On June 14, five lawmakers from the main opposition the Constitutional Democratic Party of Japan and two other opposition parties inspected the Araya exercise area and asked ministry officials about anti-tsunami measures.

Kiyomi Tsujimoto, chief of the Diet Affairs Committee of the Constitutional Democratic Party of Japan, said her party will consider submitting a no-confidence motion against the defense minister.