Auxiliary material for Paper 2008GC002188 Velocity structure of upper ocean crust at Ocean Drilling Program Site 1256 Stephen Swift Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA. Marc Reichow Department of Geology, University of Leicester, Leicester, UK. Anahita Tikku ExxonMobil Upstream Research Company, Houston, Texas, USA. Masako Tominaga Department of Oceanography, Texas A&M University, College Station, Texas, USA. Lisa Gilbert Maritime Studies Program of Williams College and Mystic Seaport, Mystic, Connecticut, USA. Swift, S., M. Reichow, A. Tikku, M. Tominaga, and L. Gilbert (2008), Velocity structure of upper ocean crust at Ocean Drilling Program Site 1256, Geochem. Geophys. Geosyst., 9, Q10O13, doi:10.1029/2008GC002188. Introduction This data set contains compressional travel time arrivals (one-way) and velocities as a function of borehole depth for the Vertical Seismic Profiles (VSPs) shot on ODP Leg 206 ("2008gc002188-ts01.txt") and IODP Expedition 312 (2008gc002188-ts02.txt"). Details on the methods used to acquire the data are described in the paper and in Shipboard Scientific Party (2003b) and Expedition 309/312 Scientists (2006). Seismograms at each receiver depth were edited to eliminate shots with low signal/noise for the compressional arrival. These seismograms were displayed and the travel time of the compressional arrival was picked using interactive software ("upicker") provided by W. Wilcox (UW). The number of seismograms for which travel times were picked varies with receiver depth depending on the number of airgun shots recorded and the signal/noise of the recording. We computed velocities by inversion of travel times using software provided by D. Lizarralde (WHOI). 1. 2008gc002188-ts01.txt One-way travel times for compressional waves recorded during the VSP shot at the end of ODP Leg 206 and interval velocities computed by inversion. Velocities are given at the top of velocity intervals. The average travel time at each receiver depth is given first. Then travel times are given for all seismograms picked. Since the number of seismograms that were picked varies between receiver depths, a value of "99.9999" is given in columns where no arrival was picked. 1.1 Column "depth", m, meters below sea floor. 1.2 Column "velocity", km/s, compressional wave velocity. 1.3 Column "time", s, average one-way travel time for all seismograms at this depth. 1.4-1.14 Column "time", s, one-way travel time for an individual seismogram. 2. 2008gc002188-ts02.txt One-way travel times for compressional waves recorded during the VSP shot at the end of IODP Expedition 312 and interval velocities computed by inversion. Velocities are given at the top of velocity intervals. The average travel time at each reciever depth is given first. Then travel times are given for all seismograms picked. Since the number of seismograms that were picked varies between receiver depths, a value of "99.9999" is given in columns where no arrival was picked. 1.1 Column "depth", m, meters below sea floor. 1.2 Column "velocity", km/s, compressional wave velocity. 1.3 Column "time", s, average one-way travel time for all seismograms at this depth. 1.4-1.14 Column "time", s, one-way travel time for an individual seismogram.