Original seismograms dataset of the 688 selected events of the July 1998 seismic swarm that struck Faial and Pico islands, in the Azores archipelago. The 688 dataset correspond to the best constrained hypocenters, that were used in the 3D tomographic modelling of the area of Dias et al. (2007), and comprises a file hyo688.out with the location of each event and corresponding P and S waves travel time picks and waveform file all SEISAN/nordic format. A file STATION0.HYP containing the seismic stations coordinates and the 1D model of Matias et al. (2007) is also provided in nordic format.