  This paper is concerned with the reconstruction issue of an inverse crack
problem in a two-dimensional bounded domain which may have a possible
application to the nondestructive evaluation of materials. It is assumed that
the domain consists of two elastic plates welded together and has some unknown
cracks on the junction line and the governing equation of in-plane displacement
is Navier's equation. The problem is to extract information about the location
of cracks from the observation data which is a single set of a loading surface
traction and the resulted in-plane displacement field on the boundary of the
domain. It is shown that the enclosure method combined with the Kelvin
transform yields explicit extraction formulae of such information from the
observation data.
