The libfern library, assocated fern binary, and inferface in sac provides a interface to:
- event searches
- download data (miniseed format)
- station searches
- apply station meta-data
- apply event meta-data
- search for available data
- convert miniseed to sac
- write miniseed and sac files
- Event Search
- Station Search
- Search based on Event
- Data Availability Search
- Data Download to miniseed
- Data Download to sac
- Event Search with libfern
- Station Search with libfern
- Data Download with libfern
| Description | Argument |
|---|---|
| Event Search | -E |
| Magntiude: 9 - 10 | -m 9/10 |
| Time: 1950 - 2020 | -t 1950/01/01 2020/01/01 |
fern -E -m 9/10 -t 1950/01/01 2020/01/01
Origin Lat. Lon. Depth Mag. Agency EventID
2011-03-11T05:46:24 38.30 142.37 29.00 9.10 mww US/official - usgs:official20110311054624120_30
2004-12-26T00:58:53 3.29 95.98 30.00 9.10 mw US/official - usgs:official20041226005853450_30
1964-03-28T03:36:16 60.91 -147.34 25.00 9.20 mw iscgem/official - usgs:official19640328033616_30
1960-05-22T19:11:20 -38.14 -73.41 25.00 9.50 mw iscgem/official - usgs:official19600522191120_30
1952-11-04T16:58:30 52.62 159.78 21.60 9.00 mw iscgem/official - usgs:official19521104165830_30
| Description | Argument |
|---|---|
| Station Search | -S |
| Time: 1999/01/01 - 1999/01/02 | -t 1999/01/01 +1day |
| Network: IU | -n IU |
| verbose: On | -v |
fern -S -t 1999/01/01 +1day -n IU
Net Sta Lat. Lon. Elev. SiteName
IU ADK 51.8823 -176.6842 130.00 Adak, Aleutian Islands, Alaska
IU AFI -13.9093 -171.7773 706.00 Afiamalu, Samoa
IU ANMO 34.9459 -106.4572 1850.00 Albuquerque, New Mexico, USA
...
IU XMAS 2.0448 -157.4457 20.00 Kiritimati Island, Republic of Kiribati
IU YAK 62.0310 129.6805 110.00 Yakutsk, Russia
IU YSS 46.9587 142.7604 150.00 Yuzhno Sakhalinsk, Russia
| Description | Argument |
|---|---|
| Event search | -E |
| Start time 160th day in 1994 | -t 1994/160 |
| Magntiude 8 - 10 | -m 8/10 |
| Station search | -S |
| Time: event origin time | -e usgs:usp0006dzc |
| Network: IU, XE | -n IU,XE |
| Radial search from event to 35 degrees | -r0/35 -e usgs:usp0006dzc |
fern -E -t 1994/160 +1d -m 8/10
Origin Lat. Lon. Depth Mag. Agency EventID
1994-06-09T00:33:16 -13.84 -67.55 631.30 8.20 mw US/HRV - usgs:usp0006dzc
fern -S -e usgs:usp0006dzc -n IU,XE -r0/35
Net Sta Lat. Lon. Elev. SiteName
IU BOCO 4.5869 -74.0432 3160.00 Bogota, Colombia
IU SJG 18.1091 -66.1500 420.00 San Juan, Puerto Rico
XE CHIT -20.0756 -66.8851 3862.00 -
...
XE SICA -17.2924 -67.7490 4065.00 -
XE TACA -18.8279 -66.7331 3810.00 -
XE YUNZ -19.1581 -65.0700 2896.00 -
# Equivalent to the following
fern -S -t 1994-06-09T00:33:16 +0m -n IU,XE -O -67.55/-13.84 -r0/35
Net Sta Lat. Lon. Elev. SiteName
IU BOCO 4.5869 -74.0432 3160.00 Bogota, Colombia
IU SJG 18.1091 -66.1500 420.00 San Juan, Puerto Rico
XE CHIT -20.0756 -66.8851 3862.00 -
...
XE SICA -17.2924 -67.7490 4065.00 -
XE TACA -18.8279 -66.7331 3810.00 -
XE YUNZ -19.1581 -65.0700 2896.00 -
| Description | Argument |
|---|---|
| Start time: Event origin time | -e usgs:usp0006dzc |
| End time: Event origin time +30 minutes | -e usgs:usp0006dzc -d +30m |
| Network: XE | -n XE |
| Channel: BHZ | -c BHZ |
fern -D available -e 'usgs:usp0006dzc' -n XE -d +30m -c BHZ
## REQUEST 1/ 1
DATACENTER=IRISDMC,http://ds.iris.edu
XE CHIT -- BHZ 1994-06-09T00:33:16 1994-06-09T01:03:16
XE CHUQ -- BHZ 1994-06-09T00:33:16 1994-06-09T01:03:16
XE COLL -- BHZ 1994-06-09T00:33:16 1994-06-09T01:03:16
...
XE SICA -- BHZ 1994-06-09T00:33:16 1994-06-09T01:03:16
XE TACA -- BHZ 1994-06-09T00:33:16 1994-06-09T01:03:16
XE YUNZ -- BHZ 1994-06-09T00:33:16 1994-06-09T01:03:16
| Description | Argument |
|---|---|
| Download miniseed data | -D miniseed |
| Start time from event origin | -e usgs:usp0006dzc |
| End time from event origin + 30 minutes | -e usgs:usp0006dzc -d +30m |
| Network: XE | -n XE |
| Channel: BHZ | -n BHZ |
fern -D miniseed -e 'usgs:usp0006dzc' -n XE -d +30m -c BHZ
Data Center: IRISDMC,http://ds.iris.edu
Writing data to fdsnws.2019.07.20.10.56.28.IRISDMC.mseed [968.00 KiB]
| Description | Argument |
|---|---|
| Download miniseed data | -D sac |
| Start time from event origin | -e usgs:usp0006dzc |
| End time from event origin + 30 minutes | -e usgs:usp0006dzc -d +30m |
| Network: XE | -n XE |
| Channel: BHZ | -n BHZ |
| Station: DOOR | -s DOOR |
fern -D sac -e 'usgs:usp0006dzc' -n XE -v -d +30m -c BHZ -s DOOR
Data Center: IRISDMC,http://ds.iris.edu
Working on file: XE.DOOR..BHZ.M.1994.160.003321.sac [ OK ]
Writing data to XE.DOOR..BHZ.M.1994.160.003321.sac [ 70.73 KiB]
Station meta data is autoomatically set if sac conversion is requested: - Station Latitude (stla) - Station Longitude (stlo) - Station Elevation (stel) - Station Depth (stdp) , always 0.0 - Component Azimuth (cmpaz) - Component Inclination (cmpinc)
Event meta data is automatically set of an event parameter is used and sac conversion is requested: - Event Latitude (evla) - Event Longitude (evlo) - Event Depth (evdp) - Event Elevation (evel), always 0.0 - Event Name (kevnm) - Origin Time (kzdate, kztime) - Reference Time (iztype) set to IO, i.e. event origin time - All other times are shifted to the reference time - The following are computed: - Distance (dist) - Great Circle Arc (gcarc) - Azimuth (az) - Back azimuth (baz)
// Contstruct a request
// Magnitude: 8 - 10
// Time: 1994/160 - 1994/161
// Depth: 400.0 - 700.0 km
// Verbose: On
request *r = event_req_new();
request_set_url(r, "https://earthquake.usgs.gov/fdsnws/event/1/query?");
event_req_set_mag(r, 8.0, 10.0);
event_req_set_depth(r, 400.0, 700.0);
event_req_set_time_range(r,
timespec64_from_yjhmsf(1994, 160, 0, 0, 0, 0),
timespec64_from_yjhmsf(1994, 161, 0, 0, 0, 0));
request_set_verbose(r, 1);
// Get request and check result
result *res = request_get(r);
if(!result_is_ok(res)) {
return -1;
}
// Parse quake xml output
int verbose = 1;
char catalog[5] = "usgs";
Event **ev = quake_xml_parse(result_data(res), result_len(res), verbose, catalog);
// Print out the events
events_write(ev, stdout);// Construct a request
// Time: 1994/160 - 1994/161
// Network: XE
// Channel: BH?
// Region: -180/180/-90/0
request *r = station_req_new();
station_req_set_time_range(r,
timespec64_from_yjhmsf(1994, 160, 0, 0, 0, 0),
timespec64_from_yjhmsf(1994, 161, 0, 0, 0, 0));
station_req_set_network(r, "XE");
station_req_set_channel(r, "BH?");
station_req_set_region(r, -180.0, 180.0, -90.0, 0.0);
request_set_verbose(r, 1);
// Get request and check result
result *res = request_get(r);
if(!result_is_ok(res)) {
return -1;
}
// Parse station xml output
int verbose = 1;
int epochs = 1;
int show_time = 1;
station **st = station_xml_parse(result_data(res), result_len(res), epochs, verbose);
if(st == NULL) {
return -1;
}
// Print out the stations
stations_write(st, show_time, stdout);size_t i = 0;
// Create a Data Request
// Origin(Lon, Lat): -67.55, -13.84 (Deep Bolivia Event 1994)
// Time: 1994/160 00:33:16 - 1994/160 01:03:16
// Network: IU,XE
// Radius: 0 - 35 degrees
fprintf(stderr, "Data Download init\n");
Event *ev = event_from_id("usgs:usp0006dzc");
fprintf(stderr, "event: %p\n", ev);
if(!ev) {
fprintf(stderr, "event undefined: %p\n", ev);
return -1;
}
request *r = data_avail_new();
data_avail_set_origin(r, -67.55, -13.84);
// Alternative using an event (Location)
// data_avail_set_origin(r, event_lon(ev), event_lat(ev));
data_avail_set_radius(r, 0.0, 35.0);
data_avail_set_network(r, "IU,XE");
data_avail_set_channel(r, "BHZ");
data_avail_set_station(r, "DOOR");
data_avail_set_time_range(r,
timespec64_from_yjhmsf(1994, 160, 0, 33, 16, 0),
timespec64_from_yjhmsf(1994, 160, 1, 03, 16, 0));
// Alternative using the event (time)
// duration d = { 0, 0 };
// duration_parse(&d, "30m");
// timespec64 start = event_time(ev);
// timespec64 end = timespec64_add_duration(start, &dur);
// data_avail_set_time(r, start, end);
request_set_verbose(r, 1);
// Get request and check result
result *res = request_get(r);
if(!result_is_ok(res)) {
printf("request is not ok\n");
return -1;
}
fprintf(stderr, "request is ok\n");
// Parse the result into a data request
data_request *dr = data_request_parse( result_data(res) );
// Print a formatted data request
data_request_write(dr, stdout);
// Write the data request to an actual file (optional)
// data_request_write_to_file(dr, "data.request");
// The request can be split into multiple pieces based on request size in MB
// Optional, but can be useful for long duration requests that last longer
// than a traditional earthquake record. It is ok, the libmseed library can
// magically merge the request files back together again, provided there
// are no data gaps.
// data_request_chunks(dr, 100);
// Download the data !!!
// Download the all of the requests
MS3TraceList *mst3k = NULL;
int save_files = 1;
int unpack_data = 1;
mst3k = data_request_download(dr, "data.request", "miniseed_prefix",
save_files, unpack_data);
// Convert miniseed trace list to sac files
sac **s = NULL;
s = miniseed_trace_list_to_sac(mst3k);
// Insert station meta data for sac files
int verbose = 1;
sac_array_fill_meta_data(s, verbose);
// Or from a file
// sac_fill_meta_data_from_file(s, verbose, "station.xml");
// sac_fill_meta_data_from_file(s, verbose, "station.json");
// Insert event meta data if event is available
// Use the Bolivian Event from above
sac_array_fill_meta_data_from_event(s, ev, verbose);
// Calculate distance, azimuth, ...
for(i = 0; i < xarray_length(s); i++) {
update_distaz(s[i]); // Function in sacio
}
// Write out sac files
// A filename is defined in an extra meta data sac header
// The extra meta data is not written out to the file
int nerr = 0;
for(i = 0; i < xarray_length(s); i++) {
sac_write(s[i], s[i]->m->filename, &nerr);
}- libmseed - https://github.com/iris-edu/libmseed
- libsacio (IRIS/LLNL) - http://ds.iris.edu/ds/nodes/dmc/forms/sac/
- libsacio (BSD) - http://https://github.com/savage13/sacio
- libcurl - https://curl.haxx.se/libcurl/ (On most systems)
- libxml2 - http://www.xmlsoft.org/ (On most systems)
- cJSON - https://github.com/DaveGamble/cJSON (Included)
- 64-bit time https://github.com/evalEmpire/y2038 (Included)
Please report issues to the project.
If you would like to contribute to the project please file Pull Requests and/or create issues for discussion at the libfern project.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this software except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.