aux_getFDSNdata function

Download seismic data from FDSN data base

The function accesses the specified FDSN internet data base(s) and downloads seismic data based on the network and station IDs and time constraints.

aux_getFDSNdata(
  start,
  duration,
  channel = "BHZ",
  network,
  station,
  url,
  link_only = FALSE,
  eseis = TRUE
)

Arguments

• start: POSIXct value, start time of the data to query.

• duration: Numeric value, length of the data to query, in seconds.

• channel: Character value, seismic channel to get. Default is "BHZ".

• network: Character vector, two-character FDSN network ID.

• station: Character vector, FDSN station ID.

• url: Character vector, FDSN URL.

• link_only: Logical vector, return only FDSN link instead of downloading and importing the data.

• eseis: Logical scalar, option to read data to an eseis

  object (recommended, see documentation of aux_initiateeseis), default is TRUE

Returns

List object with imported seismic data for each provided set of input arguments.

Details

A convenient way to get all the required input data is using the function aux_getFDSNstation before. It will return all the information in a structured way.

It is possible to use the function to process more than one data set. In this case, the arguments network, station and url

must match pairwise. The arguments start, duration and channel will be treated as constants if not also provided as vectors.

Examples

## Not run:

## get stations < 0.6 degrees away from Piz Chengalo collapse
x <- aux_getFDSNstation(centre = c(46.3, 9.6),
                        radius = 0.6,
                        access = TRUE)

## sort statiions by distance
x <- x[order(x$distance),]

## download available data
d <- aux_getFDSNdata(start = as.POSIXct(x = "2017-08-23 07:30:00", 
                                        tz = "UTC"),
                     duration = 180, 
                     network = x$network_ID, 
                     station = x$station_code, 
                     url = x$network_url)

## remove stations without available data
x <- x[!unlist(lapply(d, is.null)),]
d <- d[!unlist(lapply(d, is.null))]

## generate plots of the three nearest stations
par(mfcol = c(3, 1))

for(i in 1:3) {

  plot_signal(data = d[[i]],
              main = paste(x$ID[i], 
                           " | ",
                           round(x$distance[i], 2),
                           "distance (DD)"))
} 
## End(Not run)

See Also

aux_get_FDSNstation, read_mseed

Author(s)

Michael Dietze