The German Experimental Seismic System, known as the GERESS array, is identified in Annex 1 of the Protocol to the Comprehensive Nuclear Test-Ban Treaty (CTBT) as a primary seismic station (PS 19). Since its construction and commissioning in 1991, the performance of this array has been hampered by incidental occurrences of timing problems involving the loss of time synchronization for as many as a few array elements. During GSETT-3 (Conference of Disarmament Group of Scientific Experts Technical Test-3) and since the establishment of the Vienna International Data Centre (IDC), the array has contributed data to the CTBT monitoring system. Beginning in 1997, the German National Data Center (NDC) at the Federal Institute for Geosciences and Natural Resources (BGR) started to archive these data on CD-ROM and makes them available via Auto-DRM, notwithstanding the fact that the data may be time-corrupted. Instances have been found when up to five array elements were unsynchronized, which may lead to inconsistent array processing results. Up to now the detection and elimination of such timing errors was considered an unsolvable problem. This would certainly be true if the GERESS array were a single- (or three-) component station. However, an array provides the chance to use waveform correlation of coherent signals, as is usually provided by teleseismic events of significant magnitude, where timing differences are easily identified and measured. These large teleseismic events, unfortunately, are not frequent enough to be used on a regular and continuous basis. The only continuously available signal observed at a seismic station is microseismic noise, which, thus, is usually considered an obstacle to seismological investigations. In this study, however, we present results that this ocean-generated seismic signal can be favorably used in waveform correlation as a constant source of sufficient seismic energy. Scanning several years of GERESS waveform data allowed us …