obspy.io.nlloc - NonLinLoc file format support for ObsPy¶
This module provides read/write support for some NonLinLoc file formats.
| copyright: | The ObsPy Development Team (devs@obspy.org) |
|---|---|
| license: | GNU Lesser General Public License, Version 3 (https://www.gnu.org/copyleft/lesser.html) |
Example¶
If NonLinLoc location run was performed using one of the standard projections available in the NonLinLoc package, it is straightforward to read a NonLinLoc Hypocenter-Phase file into an ObsPy Catalog object:
>>> from obspy import read_events
>>> cat = read_events("/path/to/nlloc.hyp")
>>> print(cat)
1 Event(s) in Catalog:
2006-07-15T17:21:20.195670Z | +51.658, +7.737
>>> event = cat[0]
>>> print(event)
Event: 2006-07-15T17:21:20.195670Z | +51.658, +7.737
resource_id: ResourceIdentifier(id="smi:local/...")
creation_info: CreationInfo(author='Claudio Satriano',
creation_time=UTCDateTime(2013, 6, 21, ...),
version='NLLoc:v6.02.07')
preferred_origin_id: ResourceIdentifier(id="smi:local/...")
---------
comments: 1 Elements
picks: 5 Elements
origins: 1 Elements
>>> origin = event.origins[0]
>>> print(origin)
Origin
resource_id: ResourceIdentifier(id="smi:local/...")
time: UTCDateTime(2006, 7, 15, 17, 21, 20, 1956...)
longitude: 7.736781...
latitude: 51.657659...
depth: 1433.5... [confidence_level=68, uncertainty=...]
depth_type: 'from location'
quality: OriginQuality(...)
origin_uncertainty: OriginUncertainty(...)
creation_info: CreationInfo(author='Claudio Satriano',
creation_time=UTCDateTime(2013, 6, 21, ...),
version='NLLoc:v6.02.07')
---------
comments: 1 Elements
arrivals: 5 Elements
If, instead, NonLinLoc location run was performed in some custom coordinate system (as opposed to WGS84 with depth in meters down), we need to set up a coordinate conversion function to convert from the NonLinLoc location coordinates x, y, z to longitude, latitude and depth in kilometers. In the example, the location run was done in Gauß-Krüger zone 4 (EPSG:31468, but in kilometers for coordinates) and depth in kilometers. So we have to convert x and y (of NonLinLoc location run) to meters (as defined in EPSG:31468) and then we convert to WGS84 (EPSG:4326). The z coordinate is already in kilometers downwards and can be left as is. For the conversion we use pyproj.
>>> import pyproj
>>> proj_wgs84 = pyproj.Proj(init="epsg:4326")
>>> proj_gk4 = pyproj.Proj(init="epsg:31468")
>>> def my_conversion(x, y, z):
... x *= 1e3
... y *= 1e3
... x, y = pyproj.transform(proj_gk4, proj_wgs84, x, y)
... return x, y, z
Then, we can load the NonLinLoc Hypocenter-Phase file into an ObsPy Catalog object using read_events(), supplying our coordinate mapping function as coordinate_converter kwarg, which will be passed down to the low-level routine read_nlloc_hyp().
>>> from obspy import read_events
>>> cat = read_events("/path/to/nlloc_custom.hyp",
... coordinate_converter=my_conversion)
>>> print(cat)
1 Event(s) in Catalog:
2010-05-27T16:56:24.612600Z | +48.047, +11.646
>>> event = cat[0]
>>> print(event)
Event: 2010-05-27T16:56:24.612600Z | +48.047, +11.646
resource_id: ResourceIdentifier(id="smi:local/...")
creation_info: CreationInfo(creation_time=..., version='NLLoc:v6.00.0')
---------
picks: 8 Elements
origins: 1 Elements
>>> origin = event.origins[0]
>>> print(origin)
Origin
resource_id: ResourceIdentifier(id="smi:local/...")
time: UTCDateTime(2010, 5, 27, 16, 56, 24, 612600)
longitude: 11.64553754...
latitude: 48.04707051...
depth: 4579.4... [confidence_level=68, uncertainty=191.6063...]
...
creation_info: CreationInfo(creation_time=UTCDateTime(2014, 10, 17,
16, 30, 8), version='NLLoc:v6.00.0')
---------
comments: 1 Elements
arrivals: 8 Elements