During our cruise from Hawaii to Alaska in 2012, Murre and I come upon a small section of concrete dock mid pacific that was washed to sea by the Japanese Tsunami in 2011. Exact coordinates were 39.16.588N by 162.12.540W, 1901gmt, June 29, 2012. More photos of debris we encountered can be found here: murreandthepacific.wordpress.com