The quake hit 105 miles northeast of Gisborne at depth of 19.1 miles.
I really think though that must have been the depth below the sea bed, not the water depth as the deepest part of any ocean is 36,000+ feet or a little over 6 miles deep. So I was interpreting the depth that they were referring to, incorrectly. It is the only thing that makes sense. Since it is not very far off of shore there is really no telling how deep the water is at that distance from shore.
I got it off of the USGS.