Determination of the three-dimensional seismic structure of the crust and upper mantle in the Central Midlands of England

Summary. Teleseismic P -wave residuals relative to CWF, a permanent shortperiod seismic station on Charnwood Forest in the Central Midlands of England, have been determined for two small aperture arrays deployed over the Precambrian block of Charnwood and its surrounding Phanerozoic sediments. The data have been inverted to produce a block model of the P -wave velocity variations in the crust and upper mantle beneath the study region. The results are consistent with significant variations penetrating to a depth of at least 50 km. Low velocities are associated with two upper crustal intrusive bodies, the Caledonian Mountsorrel granodiorite and the South Leicestershire diorites. A longer-wavelength variation at lower crustal/upper mantle depths could arise from the Moho dipping to the south-west beneath the study region, and whose strike sub-parallels the dominant Charnian trend of the major basement structures in this part of Central England.