True, I suppose
... and the places where earthquakes occur are deep in the earth and not amenable to direct observation. Earthquake prediction, in the sense of saying when any specific event will occur, is a very hard problem.
Simply make the filesystem mark deleted files as "hide from directory listing, and really delete only if you need the space". Then add a couple of syscalls to examine these "recyclable" files and restore them to normal status.
Netware has a Salvage utility that relies on a filesystem with those attributes. It used to be called the Netware File System (yes, NFS). More recent versions are now called Novell Storage Services. Ported to SuSe now according to Wikipedia http://en.wikipedia.org/wiki/Novell_Storage_Services/
Swath bathymetry is how the high resolution mapping is done.
http://woodshole.er.usgs.gov/operations/sfmapping/swath.htm
"The four building blocks of the universe are fire, water, gravel and vinyl." -- Dave Barry
