MTdata cannot distinguish between fluids (aqueous or magmatic), which would cause low-viscosity, and
graphite-, serpentinite- or sulphide-rich zones, such as are commonly seen in other suture zones,
and which do not imply low-viscosity (although graphite and serpentinite do cause low yield strength). In contrast, seismic observations can directly image reflections fromfluid-rich zones or indirectly recognize small concentrations of fluids fromlowS-wave velocities. Although many changes in seismic velocity can reasonably be attributed to compositional changes,
large reductions in S-wave velocity almost certainly imply the presence of fluids.