There is a possibility that the soundings, which are depicted on the charts of the ports and harbour suffered from the Great East Japan Earthquake happened on 11th March 2011, changed. Zone of Confidence(ZOC) Diagram is adopted and the information which survey conducted after the earthquake disaster can be distinctive from before earthquake. The areas where survey conducted after earthquake happened on 11th March 2011 are filled in light blue, attributes of the ZOC are depicted on the Diagram and as good as the survey areas are drawn in red dot line on the charts. Also, the information such as soundings, etc. which were depicted on the chart before earthquake disaster is categorized as unassessed due to lack of the confidence information.