Upgrade of the New China Digital Seismograph Network

Abstract

Online Material: Figures of waveform comparison, 10th percentile noise levels, and sensor coherence. In 1980, the State Seismological Bureau (SSB) of the People’s Republic of China, the U.S. Geological Survey (USGS), and the U.S. National Science Foundation (NSF) signed the Earthquake Studies Protocol to initiate research programs for the benefit of the earthquake hazards reduction programs in both countries (Russ and Johnson, 1985). Because high‐quality seismic data are essential to earthquake studies, one of the first elements of this protocol was the establishment of the China Digital Seismograph Network (CDSN; Fig. 1 and ![Graphic][1] Table S1, available in the electronic supplement to this article.). Figure 1. Map of China and surrounding area showing the location of China Digital Seismograph Network (CDSN) and New China Digital Seismograph Network (NCDSN) stations. Black squares mark the locations of upgraded NCDSN stations; an open triangle indicates the location of station LZH (Lanzhou, Gansu Province, China), one of the original CDSN stations that was not made part of the Global Seismographic Network (GSN). Stations BJI (Baijiatuan, Beijing, China) and BJT (Baijiatuan, Beijing, China) are coincident on this scale. Open squares mark the location of neighboring GSN stations. The CDSN was designed as a national facility, building on existing Chinese observatories where possible. Implemented by the SSB Institute of Geophysics (IG) and USGS Albuquerque Seismological Laboratory (ASL), the first phase of the network was installed in 1985–1986 and consisted of nine stations (BJI, Baijiatuan; ENH, Enshi; HIA, Hailar; KMI, Kunming; LZH, Lanzhou; MDJ, Mudanjiang; QIZ, Qiongzhong; SSE, Sheshan; and WMQ, Urumqi) with network code CD. Under the terms of the original CDSN agreement, the SSB provided the equipment for five data acquisition systems, and the USGS supplied four (Institute of Geophysics et al. , 1987). The USGS systems were installed at Baijiatuan, Kunming, Lanzhou, and Mudanjiang; the SSB systems were installed … [1]: /embed/inline-graphic-1.gif