Station Metadata: What do I Need? Dr. Mary Templeton IRIS Data Management Center Data Management Workshop Bogotá, Colombia July 2014
Why is Metadata Important? To use data, you need to know where and how it was recorded: x,y,z,t How do you translate the time series to ground motion? Direction Amplitude scaling Phase shifting The data format must be understood Metadata is easiest to record before it’s forgotten Network datalesses no longer required.
Steps for Building Metadata Register your network and station names Create a dataless SEED volume Enter network information Enter information for a single station Add additional stations using the first as a “clone” Details of these steps will be covered by Tim & Rick
What do I Need? Network information FDSN network code Network name Operating institution
What do I Need? Station information Registered station code Station long name Location of the station and it’s sensors Latitude (degrees from -90 to +90) Longitude (degrees from -180 to +180) Elevation (ground surface and sensor in m) Depth (surface elevation – sensor elevation in m) No corner period needed for accelerometers
What do I Need? Station information Sensor channel orientations Angle from magnetic north to each horizontal channel (degrees from 0 to 360) Sensor wiring convention Normal: upward ground motion produces a positive Z amplitude (similar for N and E) Reverse: upward ground motion produces a negative Z amplitude (industry geophones) No corner period needed for accelerometers
What do I Need? Station information Sample rates Sensor long-period corner Sensor gain No corner period needed for accelerometers
What do I Need? No corner period needed for accelerometers Tim will touch on the SEED manual – it contains details of channel naming based on this information
What do I Need? Station information Instrument response Sensor Sensitivity Poles and zeros A0 normalization factor Datalogger Preamplifier gain Bit weight (A/D scale factor) FIR coefficients for your field acquisition settings other No corner period needed for accelerometers
What do I Need? Station information Optional Text description of instrumentation Instrument serial numbers Comments documenting timing and other data problems No corner period needed for accelerometers
What do I Need? And Finally…. Time span (epoch) for which this information is valid If any of this metadata changes, a new epoch need to be created with updated metadata Epochs must not overlap in time No corner period needed for accelerometers
About Instrument Responses The bad news This is can be the most difficult part of gathering station metadata The good news We’ve created a response library to make this easier More about this after the break!