IRIS partners with several agencies of the US Government that collect seismic data, including the National Nuclear Security Administration (NNSA). As part of its “Source Physics Experiment” program, the NNSA is conducting a series of large chemical explosions in a borehole drilled in granite. The largest explosion to date was fired in late May (read the NNSA press release), but further and even larger explosions are planned in volcanic tuff. Each explosion is recorded by many and diverse geophysical sensors, including accelerometers and broadband seismometers. Data from the SPE explosions are managed and openly distributed by IRIS Data Services.