Here is some additional information on the channel designations at a broadgand station using SEED name conventions: (SEED = Standard for the Exchange of Earthquake Data ). Note that the SEED names are different from the former channel streem descriptor names: ie VBB-Z is BHZ, LP-Z is LHZ, VLP-? is VH?, VSP-? is SH?, etc. The names do not exactly specify the sample rate, but the conventions of the IRIS stations are preferred. here is the file vbb_system_description from CCM: ---------------------------------------------------------------------- File USR/GSN/DP_LOGS/ VBB_SYSTEM_DESCRIPTION at station CCM: (This is the response to the "r" command in any data retrieval mode.) Station : CCM Cathedral Cave, Missouri Lat: 38.0557 N Lon:-91.2446 W Elev:222.5m (51 meters below the local surface) Components: Z : + = ground motion up N : + = ground motion north E : + = ground motion east Digitizer: Quanterra Q980 split system (9 24-bit channels). SEED NAMES: BHZ,BHN,BHE: Streams: VBB : 20 SPS: on 24-bit channels, from Streckeisen STS-1 seismometers. Instrument response is flat to velocity from 10 Hz to 360 sec; Sensitivities are Z = 2278 Vsec/m; N = 2142 Vsec/m; E = 2058 Vsec/m. Recorded continuously on line and on tape. LHZ,LHN,LHE: LP : 1 SPS: derived by constant-time-delay Finite Impulse Response (FIR) digital filter from VBB stream in real time, cutoff at 2.7 S period. 4x Gain. Recorded continuously. VHZ,VHN,VHE: VLP : 0.1 SPS: derived by FIR filter from LP stream in real time, cutoff at 27 S period. 4x Gain. Recorded continuously. UHZ,UHN,UHE: ULP : 0.01 SPS: derived by FIR filter from VLP stream in real time, cutoff at 270 S period. Recorded continuously. Micro-Barometer Data, as of 24 Feb. 1995: U data is direct barometer at 419.43 counts/Pascal; V data is 3600 sec high pass of U; W data is 100 sec high pass of U. BHU,BHV,BHW: U,V,W VBB: 20 SPS: on 24-bit channels, same response as STS-1s LHU,LHV,LHW; VHU,VHV,VHW; UHU,UHV,UHW: LP, VLP, and ULP barometric data also recorded continuously. Very high gain, short period channels for the CTBT (Comprehensive Test Ban Treaty) from a separate set of 1 hz seismometers: SHZ,SHN,SHE: VSP : 40 SPS: on 24-bit channels, from GS-13 seismometers. Recording continuously but NOT event detected. (The amplifiers for the GS-13's are flat to 25 hz.) EHZ,EHN,EHE: ESP : 80 SPS: on 24-bit channels, from GS-13 seismometers. Event recorded only. (online buffers; not on tape) Various SOH channels are also recorded, including STS-1 mass position (VMZ,VMN,VME), DA supply voltage (VE1,UE1), average free packets (AFP), clock drift and corrections (ACD, AFC), and DA instrument temperature (VKI). Note: FIR filter delays are accounted for in the header reported with the data. Response: Basic response for the LP, VLP, and ULP channels is flat to ground velocity from the FIR filter upper cutoff to the second-order lower corner at 360 S period. _________________________________________ Regards, Sean-Thomas __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>