February 9, 2020

The Akahata Sunday Edition dated February 9 exclusively reported that the Defense Ministry had covered up data pertaining to soft seafloors at the planned construction site for the new U.S. military base in Nago City's Henoko in Okinawa, giving both the Tokyo and Okinawa governments a shock.

The data show that the strength of the seafloors falls far below what the ministry set as a precondition for the base construction. In short, the central government has lost credibility regarding its assertion that the soft ground improvement work is feasible.

According to the Akahata Sunday Edition, the seafloor at 90 meters below the water surface in several locations are soft as "mayonnaise" and the foundation strength there is only one third the ministry-set minimum strength. The data are written in English in an appendix of a soil survey report attached to the Defense Ministry's materials submitted to the Diet.

In Japan, there is no construction equipment capable of operating 90 meters under water. Up until now, many experts have pointed out that the construction of the base is going to be very difficult because land subsidence will likely occur.

The ministry has counter-argued that soft-ground stabilization work at 70 meters below the sea surface will be enough to build the base because a 70- to 90-meter-deep stratum is "very solid". By asserting this, the ministry plans to make a design change after obtaining endorsement from the ministry's "technical study committee" for the ground solidification work. However, the ministry did not provide the data in question to the technical study committee.

A former civil engineer of a general construction contractor said, "No one can feel safe working on such soft ground. The actual data and what the technical study committee has so far seen as a basis for its examination are very different. The discussion so far has been meaningless."

Past related article:
> Mayonnaise sea bottom will lead Henoko base project to dead end [January, 22, 2019]