Earthquake catalog search

Pyrocko provides access to some online earthquake catalogs via the pyrocko.catalog module.

Searching the GlobalCMT catalog

This example demonstrates how to query the GlobalCMT [1] database for events which occurred in 2011 in northern Chile.

from pyrocko import util, model
from pyrocko.client import catalog

tmin = util.str_to_time('2011-01-01 00:00:00')  # beginning time of query
tmax = util.str_to_time('2011-12-31 23:59:59')

# create an instance of the global CMT catalog
global_cmt_catalog = catalog.GlobalCMT()

# query the catalog
events = global_cmt_catalog.get_events(
    time_range=(tmin, tmax),
    magmin=2.,
    latmin=-35.,
    latmax=-20.,
    lonmin=-76.,
    lonmax=-65.)

print('Downloaded %s events' % len(events))
print('The last one is:')
print(events[-1])

# dump events to catalog
model.dump_events(events, 'northern_chile_events.txt')

Download catalog_search_globalcmt.py

We expect to see the following output:

Downloaded 53 events
The last one is
--- !pf.Event
lat: -28.03
lon: -71.55
time: 2011-12-07 22:23:14.250000
name: 201112072223A
depth: 22800.0
magnitude: 6.106838394015895
region: NEAR COAST OF NORTHERN C
catalog: gCMT
moment_tensor: !pf.MomentTensor
  mnn: 1.16e+17
  mee: -1.24e+18
  mdd: 1.1200000000000001e+18
  mne: 1.29e+17
  mnd: 1.61e+17
  med: 1.0900000000000001e+18
  strike1: 16.540029329929244
  dip1: 24.774772153067424
  rake1: 109.14904335232158
  strike2: 175.61123518070136
  dip2: 66.6800337700307
  rake2: 81.39111828783355
  moment: 1.622772319211786e+18
  magnitude: 6.106838394015895
duration: 5.4

Search for an event in Geofon catalog

Search for an event name only in the Geofon catalog [2] using Geofon(), with a given magnitude range and timeframe.

from pyrocko import util
from pyrocko.client import catalog

tmin = util.ctimegm('2010-01-12 21:50:00')
tmax = util.ctimegm('2010-01-13 03:17:00')  # ending time of query
mag = 6.                                    # minimum magntiude (open end)

# download event information from GEOFON web page

geofon = catalog.Geofon()
event_names = geofon.get_event_names(
    time_range=(tmin, tmax),
    magmin=mag)

for event_name in event_names:
    event = geofon.get_event(event_name)
    print(event)

Download catalog_search_geofon.py

We expect to see the following output (in YAML format):

--- !pf.Event
lat: 18.37
lon: -72.55
time: 2010-01-12 21:53:11
name: gfz2010avtm
depth: 17000.0
magnitude: 7.2
region: Haiti Region
catalog: GEOFON

Footnotes

[1]	Dziewonski, A. M., T.-A. Chou and J. H. Woodhouse, Determination of earthquake source parameters from waveform data for studies of global and regional seismicity, J. Geophys. Res., 86, 2825-2852, 1981. doi:10.1029/JB086iB04p02825

[2]	GEOFON Data Centre (1993): GEOFON Seismic Network. Deutsches GeoForschungsZentrum GFZ. Other/Seismic Network. doi:10.14470/TR560404.