The following is a circular from the Republic of the Marshall Islands:
"You will have heard of the terrible consequences of the recent underground earthquake off the western tip of Sumatra and the resultant tidal waves. The effects on shipping to date have been restricted to those unfortunate ships in port.
One of the unseen consequences MAY be a change of water depth as a result of sand waves created by the tsunami, particularly in the Malacca Straits.
We all have a responsibility to the shipping community in general to observe any depths that may have changed and to make the appropriate reports.
The following procedures are recommended:
Listen for broadcasts of changes in depths from shore stations and report them to your DPA immediately if any such reductions are reported.
Ship managers are asked to consider the foregoing guidance and incorporate these actions into watchstanding procedures, especially aboard deep draft vessels transiting the Malacca Straits".