WWSSN 1
WWSSN 1 : An acronym for the World-Wide Standardized Seismograph Network, established in the early 1960s and equipped with narrow-band short-period and longperiod seismographs (see magnification curves in Fig. 3.11 ??? of Chapter 3 in this Manual). Later, several stations were upgraded for digital data acquisition, also in an intermediate period band, and operated as DWWSSN between 1981 and 1993. See: Hutt et al. (2002)