I just downloaded the data from IRIS website. I use the rdseed command
(rdseed -Rdf BH03.881815.seed) to extract the sac file. But the SAC files
do not contain any data. The seismographs are all zero trace. Could you
please help me to figure out the problem? I will put the direct link of
data below. Thanks.
The direct link for seed file is http://www.iris.edu/pub/userdata/Sizhuang_Deng/BH03.881815.seed