| Advanced Waveform Research Methods for GERESS Recordings (2006) | |||||||||||
Abstract | |||||||||||
| Two major research projects were finished and separated papers are included in this report. The first paper (Jost et al) summarizes the GERESS recordings of underground nuclear explosions. Path-specific detection thresholds at GERESS are derived for NTS, Tuamotu Archipelago, Kazakhstan, Novaya Zemlya, and Lop Nor. These empirical detection thresholds substantially deviate from those calculated from global amplitude-distance relations (i.e. Gutenbergy- Richter). This case history again casts some doubts on theoretical network capability estimates unless these are based on careful station calibration. The second paper (Bokelmann) uses three-component and conventional vertical- component array data from GERESS to separately measure polarization and slowness vectors. This data set allows to distinguish the effect of anisotropy from lateral heterogeneity. Apart from interesting geophysical conclusions about the origin of this anisotropy, the study has also implications on the combined use of directional data from arrays and three-component stations in a global monitoring network. As local anisotropy in the vicinity of the receivers influences P-wave polarization, there may result a systematic bias between slowness parameters, measured with arrays and directional data, derived from three-component stations. | |||||||||||
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