Synthetic seismograms provide a means to calibrate (groundtruth) seismic-reflection profiles to specific subsurface stratigraphic features observed in one-dimensional core and geophysical log data acquired from wells. Independently, Walker Marine Geophysical Company and Geokinetics Incorporated used velocity data from 14 borehole-compensated sonic logs as input for specialized geophysical software to generate 14 synthetic seismograms. Velocity data from the sonic logs were converted to a synthetic seismic trace using synthetic-seismogram production software, reproduced either 5 or 8 times, and placed side-by-side to resemble a seismic-reflection profile. For each well, the synthetic seismogram was used to relate geologic and geophysical well data to the respective seismic-reflection data. Stratigraphic and hydrogeologic interfaces were fit to the true wavelet traces on seismic-reflection profiles. Selected stratigraphic and hydrogeologic interfaces were identified on the basis of comparisons to published geologic and hydrogeologic frameworks. The direct correlation of key traces on the synthetic seismograms to seismic-reflection profiles was not a perfect fit; however, some disparity is common between synthetic seismograms and seismic-reflection profiles (Bruns and others, 1994) and in many cases is a result of imperfect modeling of synthetic seismograms. Bruns, T.R., Geist, E.L., and Lavoie, D.L., 1994, Chapter 21 – Synthetic seismograms, migrated seismic reflection profiles, and lithologic correlations for Leg 135 sites in the Lau Basin and Tonga Arc, in Hawkins, J.W., Parson, L.M., Allan, J.F., and others, eds., Proceedings of the Ocean Drilling Program, Scientific Results, Lau Basin; covering Leg 135 of the cruises of the drilling vessel JOIDES Resolution, Suva Harbor, Fiji, to Honolulu, Hawaii, sites 834-841, 17 December 1990-28 February 1991: Texas A and M University, Ocean Drilling Program, College Station, Texas, v. 135, p. 331-365.