Grond
The practical side
https://data.pyrocko.org/scratch/grond-presentation/How to perform a
- probabilistic ➞ bootstrap
- centroid ➞ non-linear
- moment tensor ➞ full / deviatoric / DC
- optimisation ➞ BABO
- from broadband seismograms ➞ surface waves
Requisites
Grond is incredibly flexible. Here we need:
- Seismic waveforms ➞ Continuous Mini-SEED data
- Station meta-data ➞ FDSN Station-XML
- Preliminary event origin ➞ Pyrocko basic event file
- Green's functions ➞ Pyrocko GF Store
- Grond configuration files ➞ YAML format
Project directory layout
itc-seis-dataset-2023/
├── bin/ # Downloading scripts to retrieve data and metadate
├── config/ # Grond configuration files
├── data/ # Seismic waveforms and meta-data
│ └── events/
│ ├── 2023-02-07T154852/
│ │ └── waveforms/
│ │ └── event.txt # catalog file
│ └── 2020-02-10T170049/
└── gf_stores/ # Green's functions
└── crust2_pb/
Looking at the data
$ cd ~/itc-seis-dataset-2023
$ snuffler \
data/events/2023-02-07T154852/waveforms/prepared \
--stations \
data/events/2023-02-07T154852/waveforms/ \
stations.prepared.txt \
--events \
data/events/2023-02-07T154852/event.txt
This command line is long ...
➞ Let's create a script!
Create a new shell script:
$ touch bin/look.sh # create file
$ chmod a+x bin/look.sh # make it executable
$ gedit bin/look.sh # open in editor
Enter/copy script code:
#!/bin/bash
snuffler "$1/waveforms/prepared" \
--stations "$1/waveforms/stations.prepared.txt" \
--events "$1/event.txt"
Use it:
$ bin/look.sh data/events/2023-02-07T154852 # Turkiye 02/07
$ bin/look.sh data/events/2023-02-10T170049 # Turkiye 02/10
Visual data quality control (QC)
Aftershock of the Turkiye 2023 earthquake doublet
QC: Things to look for
- Gaps
- Data artifacts
- Clipped traces
- Incorrect gain factors
- Noise patterns
- Multi-events
- Correct origin?
- Usable frequency band?
Manual modelling
with the Seismosizer Snuffling
- Open earthquake dataset with displacement (prepared)
- Make the selected event the active event (press e key)
- Filter to 0.02 - 0.08 Hz
- Select station subset
:s sari kmrs bnn dare gaz gula yoz urfa rsdy kamt - Get the Seismosizer: DCSource (builtin) panel
- Use Add Stores and add the
crust2_pbGFs - Sort by distance
- Select Common scale per station
- Select Subsort ... (Grouped by Location)
- Play with the point source parameters...
Configuring Grond
Get example configuration
$ cd ~/itc-seis-dataset-2023
$ cd config
$ gedit regional_cmt_smaller2.gronf
A walk through the configuration
%YAML 1.1
# Example: Inversion of W-Phase from teleseismic observations.
--- !grond.Config
# All file paths referenced below are treated relative to the location of this
# configuration file, here we may give a common prefix. E.g. setting it to '..'
# if the configuration file is in the sub-directory '${project_root}/config'
# allows us to give the paths below relative to '${project_root}'.
path_prefix: '..'
# Path, where to store output (run directories). The placeholder
# '${problem_name}' will be expanded to a name configured below in
# problem_config.name_template and will typically include a config identifier
# and the event name.
rundir_template: 'runs/${problem_name}.grun'
# If given, restrict to processing of listed events
#event_names:
#- 'gfz2015sfdd'
# -----------------------------------------------------------------------------
# Configuration section for dataset (input data)
#
# The placeholder '${event_name}' will be expanded to the current event. This
# enables us to use the same configuration for multiple events. The available
# events are detected by looking into possible expansions of
# dataset_config.events_path
# -----------------------------------------------------------------------------
dataset_config: !grond.DatasetConfig
# List of files with station coordinates.
events_path: 'data/events/${event_name}/event.txt'
stations_stationxml_paths:
- 'data/events/${event_name}/waveforms/stations.koeri.0.xml'
- 'data/events/${event_name}/waveforms/stations.koeri.1.xml'
# List of directories with raw waveform data
waveform_paths: ['data/events/${event_name}/waveforms/raw']
# List of stations/components to be excluded according to their STA, NET.STA,
# NET.STA.LOC, or NET.STA.2LOC.CHA codes
blacklist: []
# List of files with additional exclusion lists (one entry per line, same
# format as above)'
responses_stationxml_paths:
- 'data/events/${event_name}/waveforms/stations.koeri.0.xml'
- 'data/events/${event_name}/waveforms/stations.koeri.1.xml'
# Apply correction factors from station corrections.
apply_correction_factors: false
# Extend incomplete seismic traces
extend_incomplete: true
# -----------------------------------------------------------------------------
# Configuration section for the observational data fitting
#
# This defines the objective function to be minimized in the optimisation. It
# can be composed of one or more contributions, each represented by a
# !grond.*TargetGroup section.
# -----------------------------------------------------------------------------
target_groups:
- !grond.WaveformTargetGroup
# Normalisation family (see the Grond documentation for how it works).
# Use distinct normalisation families when mixing misfit contributors with
# different magnitude scaling, like e.g. cross-correlation based misfit and
# time-domain Lx norm.
normalisation_family: 'td'
# Just a name used to identfy targets from this group. Use dot-separated path
# notation to group related contributors
path: 'td.full'
# Epicentral distance range of stations to be considered in meter
distance_min: 100e3
distance_max: 250e3
# Names of components to be included. Available: N=north, E=east, Z=vertical
# (up), R=radial (away), T=transverse (right)
channels: ['Z', 'T']
# How to weight contributions from this group in the global misfit
weight: 1.0
# subsection on how to fit the traces
misfit_config: !grond.WaveformMisfitConfig
# Frequency band [Hz] of acausal filter (flat part of frequency taper)
fmin: 0.025
fmax: 0.075
# Factor defining fall-off of frequency taper (zero at fmin/ffactor and
# fmax*ffactor)
ffactor: 1.5
# Time window to include in the data fitting. Times can be defined offset
# to given phase arrivals. E.g. '{stored:P}-600' would mean 600 s
# before arrival of the phase named 'P'. The phase must be defined in the
# travel time tables in the GF store.
tmin: '{stored:any_P}'
tmax: '{vel_surface:2.5}'
# tfade: 120.0
# How to fit the data (available: 'time_domain', 'frequency_domain',
# 'log_frequency_domain', 'absolute', 'envelope', 'cc_max_norm')
domain: 'time_domain'
# If non-zero, allow synthetic and observed traces to be shifted
# against each other by up to +/- the given value [s].
tautoshift_max: 1.0
# If non-zero, a penalty misfit is added for non-zero shift values.
# The penalty value is computed as
# autoshift_penalty_max * normalization_factor * tautoshift**2 / tautoshift_max**2
autoshift_penalty_max: 0.05
# For L1 norm: 1, L2 norm: 2, etc.
norm_exponent: 1
# How to interpolate the Green's functions (available choices:
# 'nearest_neighbor', 'multilinear'). Choices other than 'nearest_neighbor'
# may require dense GF stores to avoid aliasing artifacts in the forward
# modelling.
interpolation: 'nearest_neighbor'
# Name of the GF Store to use
store_id: 'crust2_pb'
# limit number of targets to N, keeping a good coverage
# limit: 40
# -----------------------------------------------------------------------------
# Definition of the problem to be solved
#
# In this section the source model to be fitted is chosen, the parameter space
# defined, and how to combine the misfit contributions defined in the
# target_groups section above.
#
# The marker !grond.CMTProblemConfig selects a centroid moment tensor source
# model.
# -----------------------------------------------------------------------------
problem_config: !grond.CMTProblemConfig
# Name used to identify the output
name_template: 'cmt_${event_name}_full_onlyZT'
# Definition of model parameter space to be searched in the optimisation
ranges:
# Time relative to hypocenter origin time [s]
time: '-5 .. 15 | add'
# Centroid location with respect to hypocenter origin [m]
north_shift: '-20e3 .. 20e3'
east_shift: '-20e3 .. 20e3'
depth: '1e3 .. 20e3'
# Range of magnitudes to allow
magnitude: '3.7 .. 6.5'
# Relative moment tensor component ranges (don't touch)
rmnn: '-1.41421 .. 1.41421'
rmee: '-1.41421 .. 1.41421'
rmdd: '-1.41421 .. 1.41421'
rmne: '-1 .. 1'
rmnd: '-1 .. 1'
rmed: '-1 .. 1'
# Source duration range [s]
duration: '1. .. 10.'
# Clearance distance around stations (no models with origin closer than this
# distance to any station are produced by the sampler)
distance_min: 1e3
# Type of moment tensor to restrict to (choices: 'full', 'deviatoric', 'dc')
mt_type: 'full'
# How to combine the target misfits. For L1 norm: 1, L2 norm: 2, etc.
norm_exponent: 1
# -----------------------------------------------------------------------------
# Configuration of pre-optimisation analysis phases.
# determined during this phase.
# -----------------------------------------------------------------------------
#
analyser_configs:
# Balancing weights are determined with this analyser
- !grond.TargetBalancingAnalyserConfig
# Number of models to forward model in the analysis, larger number -> better
# statistics)
niterations: 1000
#- !grond.NoiseAnalyserConfig
# pre_event_noise_duration: 200.
# phase_def: '{stored:any_P}'
# statistic: 'std'
# mode: 'weeding'
# cutoff: 2.0
# cutoff_exception_on_high_snr: 3.0
# -----------------------------------------------------------------------------
# Configuration of the optimisation procedure
# -----------------------------------------------------------------------------
optimiser_config: !grond.HighScoreOptimiserConfig
# Number of bootstrap realisations to be tracked simultaneously in the
# optimisation
nbootstrap: 100
# stages of the sampler. Start with uniform sampling of the model space
# (!grond.UniformSamplerPhase), then narrow down to the interesting regions
# (!grond.DirectedSamplerPhase).
sampler_phases:
- !grond.UniformSamplerPhase
# Number of iterations
niterations: 1000
- !grond.DirectedSamplerPhase
# Number of iterations
niterations: 15000
# Multiplicator for width of sampler distribution at start of this phase
scatter_scale_begin: 2.0
# Multiplicator for width of sampler distribution at end of this phase
scatter_scale_end: 0.8
# -----------------------------------------------------------------------------
# Configuration section for synthetic seismogram engine
#
# Configures where to look for GF stores.
# -----------------------------------------------------------------------------
engine_config: !grond.EngineConfig
# Whether to use GF store directories listed in ~/.pyrocko/config.pf
gf_stores_from_pyrocko_config: false
# List of directories with GF stores
gf_store_superdirs: ['gf_stores']
Preflight checks
$ grond check config/regional_cmt_smaller2.gronf \
2023-02-07T154852
Run optimization
$ grond go config/regional_cmt_smaller2.gronf \
2023-02-07T154852
Create report
$ grond report \
runs/cmt_2023-02-07T154852_full_onlyZT.grun
Understanding the optimizer
Single chain
Global + 3 bootstrap chains
Illposed, no eccentricity correction
Illposed, eccentricity correction applied
Bimodal, standard deviation from high score models
Bimodal, standard deviation from median density