The selected seismometer channel option is applied before receiving the data from IRIS:
The Seismometer Channel Option allows you to specify which channel(s) you would like to receive data for. An explanation of seismometer channel codes can be found on the IRIS website here: https://ds.iris.edu/ds/nodes/dmc/tools/data_channels/#. In the channel code the last value represents sensor orientation, where N/E are the North/East cardinal directions and Z is vertical. 1/2/3 are non-cardinal orientations, which generally occur in seismometer data when an instrument is deployed that is not correctly aligned with geographic North or is horizontally tilted.
Here are the options:
Vertical Velocity (High-Rate/Low-Rate Overlaid In Plots): High-rate and low-rate vertical velocity data will be overlaid and plotted on one graph. For broadband seismometers, this will be H- or C-band for the high-rate channel and M- or L-band for the low-rate channel depending on the requested time range. For short period seismometers, this will be high-rate E-band and low-rate M- or L-band.
Oceans 3.0 API filter: dpo_seismometerChannel=*Z
High-Rate Vertical Velocity: High-rate vertical velocity data will be plotted on one graph. For broadband seismometers, this will be H- or C-band. For short period seismometers, this will be E-band.
Oceans 3.0 API filter: dpo_seismometerChannel=HHZ
Low-Rate Vertical Velocity: Low-Rate vertical velocity data will be plotted on one graph. For broadband and short period seismometers, this will be M- or L-band depending on the requested time range.
Oceans 3.0 API filter: dpo_seismometerChannel=MHZ
High-Rate Velocity - All Components: All high-rate velocity data will be plotted on separate graphs. For broadband seismometers this will be H- or C-band. For short period seismometers this will be E-band.
Oceans 3.0 API filter: dpo_seismometerChannel=HH*
Low-Rate Velocity - All Components: All low-rate velocity data will be plotted on separate graphs. For broadband and short period seismometers this will be M- or L-band.
Oceans 3.0 API filter: dpo_seismometerChannel=MH*
Horizontal Acceleration (High Rate/Low Rate Overlaid in Plots): High-rate and low-rate horizontal acceleration data will be plotted and overlaid on one graph, where high-rate will be C- or H-band and low-rate will be M-band.
Oceans 3.0 API filter: dpo_seismometerChannel=*N12
High-Rate Horizontal Acceleration: High-rate horizontal acceleration data will be plotted on one graph for C- or H-band.
Oceans 3.0 API filter: dpo_seismometerChannel=CN12
Low-Rate Horizontal Acceleration: Low-rate horizontal acceleration data will be plotted on one graph for M-band.
Oceans 3.0 API filter: dpo_seismometerChannel=MN12
High-Rate Acceleration - All Components: All high-rate acceleration data will be plotted on separate graphs for C- or H-band.
Oceans 3.0 API filter: dpo_seismometerChannel=CN*
Low-Rate Acceleration - All Components: All low-rate acceleration data will be plotted on separate graphs for M-band.
Oceans 3.0 API filter: dpo_seismometerChannel=MN*
Velocity - All Components (High Rate/Low Rate Overlaid in Plots): High-rate and low-rate velocity data will be plotted and overlaid on one graph for each orientation. For broadband seismometers, this will be H-band for high-rate and M- or L-band for low-rate depending on the requested time range. For short period seismometers, this will be E-band for high-rate and M- or L-band for low-rate.
Oceans 3.0 API filter: dpo_seismometerChannel=*H*
Acceleration - All Components (High Rate/Low Rate Overlaid in Plots): High-rate and low-rate acceleration data will be plotted and overlaid on one graph for each orientation. For broadband accelerometers, this will be C- and/or H-band. For long period accelerometers, this will be M-band.
Oceans 3.0 API filter: dpo_seismometerChannel=*N*
All Channels (High-Rate/Low-Rate Channels Overlaid In Plots): The All Channels Option will plot all available channels for the seismometer including velocity and accelerometer data, as well as pressure data. The high-rate and low-rate velocities and accelerations will be overlaid with matching orientations. If the selected output format is MAT file or miniSEED, then mass position will also be included.
Oceans 3.0 API filter: dpo_seismometerChannel=All
The Oceans 3.0 API filter parameter values listed above for
Where N/E are the North/East cardinal directions, Z is vertical, and 1/2/3 are non-cardinal orientations. It is possible for the 'All Channels' option (bottom of table) to return channels not included in the other options, such as the low-rate pressure data in the down-hole orientation ( |
Note: A change in sample rate occurred in 2013 for all seismometers causing the low-rate channels to change from LHZ, LHE, LHN, LNZ, LNE and LNN to MHZ, MHE, MHN, MNZ, MNE and MNN.
The IRIS channel code is applied in the file mode field at the end of the file name after the date, separated with a '-'. If there is more than one, then they are listed (only occurs for overlaid plots), example: '-EHZ-MHZ'.