Station Metadata What do I Need Dr Mary

Station Metadata: What do I Need? Dr. Mary Templeton IRIS Data Management Center Managing Data from Seismic Networks September 9 -17 2015 Hanoi, Vietnam

Why is Metadata Important? n To use data, you need to know where and how it was recorded: n n x, y, z, t How do you translate the time series to ground motion? n n n Direction of motion recorded Amplitude scaling Phase shifting The data format must be understood Metadata is easiest to record before it’s forgotten

Steps for Building Metadata n Register your network and station names n Networks: http: //www. fdsn. org/networks/request/ n n n You now have the ability to provide or request the FDSN creates a Digital Object Identifier (DOI) for you network Stations: http: //www. isc. ac. uk/registries/registration/ Create a dataless SEED volume Enter network information Enter information for a single station Add additional stations using the first as a “clone”

What do I Need? n Network information n FDSN network code Network name Operating institution

What do I Need? n Station information n Registered station code Station long name Location of the station and it’s sensors Latitude (degrees from -90 to +90) n Longitude (degrees from -180 to +180) n Elevation (ground surface and sensor in m) n Depth (surface elevation – sensor elevation in m) n

What do I Need? n Station information n Sensor channel orientations n n 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) n Reverse: upward ground motion produces a negative Z amplitude (industry geophones) n

What do I Need? n Station information n Sample rates Sensor long-period corner Sensor gain

What do I Need?

What do I Need? n Station information n Instrument response n Sensor n n Sensitivity Poles and zeros A 0 normalization factor Datalogger n n Preamplifier gain Bit weight (A/D scale factor) FIR coefficients for your field acquisition settings other

What do I Need? n Station information n Optional Text description of instrumentation n Instrument serial numbers n Comments documenting timing and other data problems n

What do I Need? n And Finally…. n Time span (epoch) for which this information is valid If any of this metadata changes, a new epoch needs to be created with updated metadata n Epochs must not overlap in time�- you must close the previous epoch (edit the end time) whenever you add a new epoch for the same channel. n

About Instrument Responses n The bad news n n This is can be the most difficult part of gathering station metadata The good news n n We’ve created a response library to make this easier More about this after the break!