eseis (version 0.8.0)

read_fdsn: Download and import seismic data from an FDSN service provider

Description

The function implements download and import of seismic data from FDSN data providers via the fdsnws-dataselect service (see https://www.fdsn.org/webservices/). It is basically a wrapper for the query approach.

Usage

read_fdsn(
  start,
  duration,
  station,
  network,
  component = "BHZ",
  url,
  eseis = TRUE,
  ...
)

Value

An eseis object or a list with the time ($time) and $signal vectors as well as meta information.

Arguments

start

POSIXct value, start time of the data to import. If lazy users only submit a text string instead of a POSIXct object, the function will try to convert that text string, assuming UTC as time zone.

duration

Numeric value, duration of the data to import, in seconds.

station

Character vector, optional 3-4-digit FDSN station ID.

network

Character vector, optional 2-digit FDSN network ID.

component

Character vector, seismic component to search for. If omitted, the function will look for "BHZ" by default.

url

Chracter vector, URL of the FDSN data provider. Should be of the form "http://service.iris.edu", i.e., without further URL parts. URLs can be submitted as a vector. If omitted, the function will look in the two most comprehensive providers, i.e. url = c("http://service.iris.edu", "http://eida-federator.ethz.ch"). See details for further information.

eseis

Logical value, option to read data to an eseis object (recommended, see documentation of aux_initiateeseis), default is TRUE

...

Additional query arguments sent to the FDSN data provider. See details for available argument names and conventions.

Author

Michael Dietze

Details

The FDSN (International Federation of Digital Seismograph Networks) provides access to a large number of seismic stations worldwide. The data are organised by network, station, component and further arguments. In order to use the eseis function read_fdsn, one must know at least the former three criteria for the data of interest. A list of networks is available here: https://www.fdsn.org/networks/. The function expects the 2-digit network code, the 3- or 4-digit station code, a single seismic component ID, and the URL to the data archive. Additional query arguments can be added (and must be added to point at a single seismic trace to download and import). A complete list of query arguments is available here: https://www.fdsn.org/webservices/fdsnws-dataselect-1.1.pdf.

For each network listed there, one can find the URL that gives access to the data (if existing) under "Data Access". Note that the function only requires the first URL part, e.g., https://geofon.gfz-potsdam.de.

Examples

if (FALSE) {

## read and plot 10 min of data from Ecuador, specifying the component
s <- read_fdsn(start = "2020-05-16 22:42:00",
               duration = 360, 
               station = "IMBA", 
               network = "EC", 
               component = "HHZ")
plot(s)

## read and plot 10 min of data from Germany, specifying the URL
s <- read_fdsn(start = "2017-03-21 04:38:00",
               duration = 360, 
               station = "RGN", 
               network = "GE", 
               url = "http://geofon.gfz-potsdam.de")
plot(s)

}