Looking at the GeoResonance "presentations", I wonder, how can a scan for titanium have a larger area and be more intense than that for aluminum? A B772 is 70% Al and only 7% Ti by weight. While aluminum covers most of the aircraft structure, titanium is located at strategic locations such as engines, landing gear, ducting, and is used as shimming material to prevent "potential" between aluminum and CFRP (e.g. prevent the risk of galvanic corrosion of aluminum).
https://au.news.yahoo.com/sa/a/23036...e-found-mh370/
http://www.southampton.ac.uk/~jps7/A...0materials.pdf