According to the Guide to International Data Exchange through the WDCs (Washington, 1973) World Data Center for Solid Earth Geophysics, Boulder and World Data Center for Solid Earth Physics, Moscow have accumulated copies of seismograms for all shocks with surface-wave magnitude equal or greater than 7.5 as indicated on PDE cards issued by the USGS beginning from 1974. Records of weaker shocks of special interest with M>6 have been submitted only after a special decision of scientific advisors. WDCs in Boulder and Moscow have exchanged for these data. The present collection consists of seismogram copies of 35-mm microfilm and microfiche for the events enumerated in the list .

Users can request by e-mail copies of these data according to station list . Request should contain the earthquake date, origin time, and station list.