scautopick

Phase detection and picking on waveforms.

Description

scautopick applies threshold monitoring by searching for waveform anomalies in form of changes in amplitudes. It is applied for detecting phase arrivals and and for measuring related features and amplitudes. The phase arrivals are typically associated by modules like scautoloc for locating the source.

Note

Instead of detecting phase arrivals for source location, scautopick can also be applied for detecting simple amplitude exceedence applying filters like the MAX() filter. Exceedences are reported as picks and can be processed further, e.g. by scalert.

Phase Detections

scautopick detects phase onsets for generating picks. Initally, it searches for detections on the waveform streams defined by global bindings.

P picks

A primary detector is applied first. When a detection is found, ‘P’ is by default assigned to the guess of the phase type (phaseHint). The actual guess can be configured by phaseHint. By default the primary detector applies a robust STA/LTA detector (STALTA() filter) to waveforms for making detections. Other detection filters and filter chains can be choosen from the list of SeisComP filters. A guess of the pick type may be defined by phaseHint.

Waveforms are typically pre-filtered before the actual STALTA() filter. Without further configuration a running-mean highpass, a cosine taper and a Butterworth bandpass filter of third order with corner frequencies of 0.7 and 2 Hz are applied before the STALTA() filter. The entire filter sequence is configurable by filter, module configuration, or detecFilter, binding configuration.

Once the STA/LTA ratio has reached a configurable threshold (by default 3) for a particular stream, a pick is set to the time when this threshold is exceeded (pick time) and the picker is set inactive. The picker is reactivated for this stream once the STA/LTA ratio falls to the value of 1.5 (default).

The trigger thresholds are configurable:

Initial detections can be further adjusted by a second-stage phase re-picker (post picker) as defined by picker. The re-picker should be tuned carefully and global bindings parameters picker.* should be configured accordingly.

After having detected a phase, the re-picker will be inactive and accept no further detection until

  • The amplitudes measured after filtering (filter in module configuration or detecFilter in binding configuration) fall below the thresholds.triggerOff (module configuration) or trigOff (binding configuration) and

  • Amplitudes, A_{trigger}, measured after filtering reach or exceed a threshold determined by T_{minOffset} (thresholds.minAmplOffset), T_{dead} (thresholds.deadTime) and the amplitude of the previous pick, A_{prev}:

    A_{trigger} \ge T_{minOffset} + A_{prev} * exp\left(-(dt/T_{dead})^2\right)

    if T_{dead} > 0. Otherwise:

    A_{trigger} \ge T_{minOffset}

    Here, dt is the time passed since the last pick. T_{minOffset} (thresholds.minAmplOffset) is typically similar to the trigger threshold, thresholds.triggerOn (module configuration) or trigOn (binding configuration).

S picks

Based on the inital detection or pick a secondary picker may applied be applied, e.g., for picking S phases as defined by spicker. The secondary picker is halted as soon as new detections are made unless killPendingSPickers is inactive.

As for the re-picker also the spicker should be tuned carefully and global bindings parameters spicker.* should be set.

Second-stage pickers available by configuration of picker or spicker

picker name

phase

picker

spicker

global bindings parameters

AIC

P, configurable: phaseHint

x

picker.AIC.*

BK

P, configurable: phaseHint

x

picker.BK.*

S-L2

S

x

spicker.L2.*

Feature extraction

For extracting features related to picks such as polarization parameters configure fx and the related global bindings parameters fx.*.

Amplitude Measurements

The second task of scautopick is to calculate amplitudes of a given type for the corresponding magnitude type (see scamp for a list of amplitude types and scmag for the magnitude types). Such amplitudes are required by:

  • scautoloc for associating phase picks and generating a source location

  • EEW (earthquake early warning) systems in order to provide raüid amplitudes for magnitudes as soon as source locations are available.

The time window for measuring amplitudes starts at the pick time. The window length is constant and specific to the amplitude type. It can be adjusted in global bindings. For example mb is calculated for a fixed time window of 30 s after the pick, mB for time window of 60s, for MLv a time window of 150 s is estimated to make sure that S-arrivals are inside this time window. The pre-calculated amplitudes are sent out and received by the magnitude tool, scmag. The fixed time window poses a limitation to EEW system. Howver, a speed-up is available with amplitudes.enableUpdate. Read the scamp documentation for more details on amplitude measurements.

Modes of Operation

scautopick usually runs in the background connected to a real-time data source such as Seedlink. This is referred to as online mode. Another option to run scautopick is on offline mode with files.

Real-time

In real-time mode the workflow draws like this:

  • scautopick reads all of its binding parameters and subscribes to stations defined by global binding parameters where detecEnable is set to true.

  • The data time window requested from the data source is [system-leadTime, NULL] meaning an open end time that causes SeedLink to stream real-time data if no more data are in the buffers.

  • Each incoming record is filtered according to detecFilter.

  • The samples are checked for exceedance of trigOn and in the positive case either a post picker (picker) is launched or a Pick object will be sent.

  • If sendDetections is set to true, a trigger will be sent in any case for e.g. debugging.

  • After the primary stage has finished (detector only or picker) secondary pickers will be launched if configured with spicker.

These steps repeat for any incoming record.

To run scautopick in the background as a daemon module enable and start it

$ seiscomp enable scautopick
$ seiscomp start scautopick

For executing on the command line simply call it with appropriate options, e.g.

$ seiscomp exec scautopick -h

Non-real-time

Note

Due to code changes in the file data source, the command line option –playback is essential for non-real-time operation. Otherwise a real-time time window is set and all records are most likely filtered out.

To tune scautopick or to do playbacks it is helpful to run scautopick not with a real-time data source but on a defined data set, e.g. a multiplexed sorted miniSEED volume. scautopick will apply the same workflow as in online mode but the acquisition of data records has to change. If the input data (file) has been read, scautopick will exit and furthermore it must not ask for a particular time window, especially not for a real-time time window. To accomplish that the command-line parameter `--playback` has to be used. Example:

$ scautopick --playback -I data.mseed

This call will process all records in data.mseed for which bindings exist and send the results to the messaging. If all data records are processed, scautopick will exit. The processing steps are similar to the online mode.

Use the `--ep` for offline processing without messaging. The results are printed in SCML format. Example:

$ scautopick --playback -I data.mseed --ep -d [type]://[host]/[database] > picks.xml

Module Configuration

etc/defaults/global.cfg
etc/defaults/scautopick.cfg
etc/global.cfg
etc/scautopick.cfg
~/.seiscomp/global.cfg
~/.seiscomp/scautopick.cfg

scautopick inherits global options.

ringBufferSize

Default: 300

Type: int

Unit: s

Defined the record ringbuffer size in seconds.

leadTime

Default: 60

Type: int

Unit: s

The leadTime defines the time in seconds to start picking on waveforms before current time.

playback

Default: false

Type: boolean

If enabled, picks can be made on waveforms which are older than current time - "leadTime". Current time is the time when the module was started. This allows to pick historic data in real-time playbacks which are preserving the record times. See e.g. the "msrtsimul" module. This option deactivates "leadTime". Activate only for playbacks.

initTime

Default: 60

Type: int

Unit: s

The initTime defines a time span in seconds for that the picker is blind after initialization. This time is needed to initialize the filter and depends on it.

gapInterpolation

Default: false

Type: boolean

Interpolate gaps linearly? This is valid for gaps shorter than thresholds.maxGapLength.

useAllStreams

Default: true

Type: boolean

If enabled, all streams that are received by the picker are used for picking. This option has only effect if a file is used as input which contains more data than the picker requests. If connected to a waveform server such as SeedLink, the picker will only receive the data it is subscribed to.

filter

Default: "RMHP(10)>>ITAPER(30)>>BW(4,0.7,2)>>STALTA(2,80)"

Type: string

The default filter used for making detections. Station-specific configurations (bindings) override this value.

timeCorrection

Default: -0.8

Type: double

Unit: s

The time correction applied for a pick. Station-specific values (bindings) override this value.

picker

Type: string

The re-picker to use. By default only simple detections are emitted as picks. To enable re-picking on a time window around the detection, an algorithm (plugin) can be defined with this parameter.

Currently available: "AIC", "BK" or "GFZ".

More options may be available by plugins. Configure related parameters in global bindings.

phaseHint

Default: P

Type: string

Phase hint to be assigned to the pick made by the primary picker.

sendDetections

Default: false

Type: boolean

If enabled and "picker" is configured, then initial detections are sent as well. To distinguish between detections and picks the evaluation status of the pick is set to "rejected". This is meant to be a debug option which can be used to compare detections and picks by their evaluation status.

spicker

Type: string

The secondary picker to use, e.g., for picking S-phases. Currently available is: "S-L2". More options may be available by plugins. Configure related parameters in global bindings.

killPendingSPickers

Default: true

Type: boolean

If enabled, all secondary pickers that were triggered by a previous pick will be terminated when a new detection or pick has been found. This aims to avoid the case where an S phase is wrongly picked as P but would also be picked as S by the secondary picker. But suppressing the S pick can lead to undesired results. It might be better in some situations to have two picks (P and S) instead only a wrong P.

extraPickComments

Default: false

Type: boolean

If enabled and "picker" or "spicker" is configured, extra comments will be added to the resulting pick.

Supported comments:

SNR: added if SNR >= 0, comment id is "SNR"

fx

Type: string

Configures the feature extraction type to use. Currently available: "DFX". Configure related parameters in global bindings.

When configured, the usability of the features for locating depends on the used locator, e.g. LOCSAT. Read the locator’s documentation and configuration parameters.

amplitudes

Default: MLv, mb, mB

Type: list:string

The amplitude types to be computed by the picker based on picks.

Note

thresholds.* Threshold parameters for the primary picker.

thresholds.triggerOn

Default: 3

Type: double

For which value on the filtered waveforms is a pick detected. Station specific values override this value.

thresholds.triggerOff

Default: 1.5

Type: double

The value the filtered waveforms must reach to enable detection again. Between triggerOn and triggerOff the picker is blind and does not produce picks. Station specific values override this value.

thresholds.maxGapLength

Default: 4.5

Type: double

Unit: s

The maximum gap length in seconds to handle. Gaps larger than this will cause the picker to be reset.

thresholds.amplMaxTimeWindow

Default: 10

Type: double

Unit: s

The time window used to compute a maximum (snr) amplitude on the filtered waveforms.

thresholds.deadTime

Default: 30

Type: double

Unit: s

The time used together with measured amplitude and thresholds.minAmplOffset for scaling the amplitude below which the picker is inactive after a P pick. Read the documentation!

thresholds.minAmplOffset

Default: 3

Type: double

The amplitude used together with measured amplitude and thresholds.deadTime for scaling the amplitude below which the picker is inactive after a P pick. The value is typically similar to the trigger threshold. Read the documentation!

amplitudes.enableUpdate

Type: list:string

Configure a list of magnitude types. Update and send amplitudes for these magnitudes as soon as data are available. Do not wait for complete time windows. Only magnitudes computed by scautopick as given by the amplitudes parameter are considered. This option is for rapid magnitude estimation and EEW.

WARNING: This option increases the load on the system!

connection.amplitudeGroup

Default: AMPLITUDE

Type: string

Message group for sending amplitudes to.

Bindings Parameters

detecEnable

Default: true

Type: boolean

Enables/disables picking on a station.

detecFilter

Default: "RMHP(10)>>ITAPER(30)>>BW(4,0.7,2)>>STALTA(2,80)"

Type: string

Defines the filter to be used for picking.

trigOn

Default: 3

Type: double

For which value on the filtered waveform is a pick detected.

trigOff

Default: 1.5

Type: double

The value the filtered waveform must reach to enable a detection again.

timeCorr

Default: -0.8

Type: double

Unit: s

The time correction applied to a pick.

sensitivityCorrection

Default: false

Type: boolean

Defines whether the detector applies sensitivity correction (applying the gain) or not in advance to filter the data.

Command-Line Options

Generic

-h, --help

Show help message.

-V, --version

Show version information.

--config-file arg

Use alternative configuration file. When this option is used the loading of all stages is disabled. Only the given configuration file is parsed and used. To use another name for the configuration create a symbolic link of the application or copy it. Example: scautopick -> scautopick2.

--plugins arg

Load given plugins.

-D, --daemon

Run as daemon. This means the application will fork itself and doesn’t need to be started with &.

--auto-shutdown arg

Enable/disable self-shutdown because a master module shutdown. This only works when messaging is enabled and the master module sends a shutdown message (enabled with --start-stop-msg for the master module).

--shutdown-master-module arg

Set the name of the master-module used for auto-shutdown. This is the application name of the module actually started. If symlinks are used, then it is the name of the symlinked application.

--shutdown-master-username arg

Set the name of the master-username of the messaging used for auto-shutdown. If "shutdown-master-module" is given as well, this parameter is ignored.

Verbosity

--verbosity arg

Verbosity level [0..4]. 0:quiet, 1:error, 2:warning, 3:info, 4:debug.

-v, --v

Increase verbosity level (may be repeated, eg. -vv).

-q, --quiet

Quiet mode: no logging output.

--component arg

Limit the logging to a certain component. This option can be given more than once.

-s, --syslog

Use syslog logging backend. The output usually goes to /var/lib/messages.

-l, --lockfile arg

Path to lock file.

--console arg

Send log output to stdout.

--debug

Execute in debug mode. Equivalent to --verbosity=4 --console=1 .

--log-file arg

Use alternative log file.

Messaging

-u, --user arg

Overrides configuration parameter connection.username.

-H, --host arg

Overrides configuration parameter connection.server.

-t, --timeout arg

Overrides configuration parameter connection.timeout.

-g, --primary-group arg

Overrides configuration parameter connection.primaryGroup.

-S, --subscribe-group arg

A group to subscribe to. This option can be given more than once.

--content-type arg

Overrides configuration parameter connection.contentType.

--start-stop-msg arg

Set sending of a start and a stop message.

Database

--db-driver-list

List all supported database drivers.

-d, --database arg

The database connection string, format: service://user:pwd@host/database. "service" is the name of the database driver which can be queried with "--db-driver-list".

--config-module arg

The config module to use.

--inventory-db arg

Load the inventory from the given database or file, format: [service://]location .

--db-disable

Do not use the database at all

Records

--record-driver-list

List all supported record stream drivers.

-I, --record-url arg

The recordstream source URL, format: [service://]location[#type]. "service" is the name of the recordstream driver which can be queried with "--record-driver-list". If "service" is not given, "file://" is used.

--record-file arg

Specify a file as record source.

--record-type arg

Specify a type for the records being read.

Mode

--offline

Do not connect to a messaging server and do not use the database.

--playback

Switches to playback mode which does not request a particular time window from the input data source. This implies that all records are forwarded to scautopick if files are being used. Without this option scautopick sets the requested start time to NOW-leadTime and therefore would not work anymore with older datasets in offline mode or when running playbacks.

--ep

Outputs an XML event parameters file containing all picks and amplitudes. This option implies offline.

--amplitudes arg

Enables or disables computation of amplitudes.

--test

Runs the picker as usual but does not send any messages. This can be useful to test the picker within a running system.

--dump-config

Dumps the current configuration and exits. Station configuration is only read if the picker connects to the messaging and the database. In offline mode it will only dump the application specific setting unless a station.conf file is provided.

--dump-records

This option only works in combination with --offline. It will dump the data of an amplitude processor if it completed processing successfully and a new amplitude is available. The output format is a simple ASCII format.

Settings

--filter filter

Overrides configuration parameter filter.

--time-correction time

Overrides configuration parameter timeCorrection.

--buffer-size timespan

Overrides configuration parameter ringBufferSize.

--before timespan

Overrides configuration parameter leadTime.

--init-time timespan

Overrides configuration parameter initTime.

--trigger-on arg

Overrides configuration parameter thresholds.triggerOn.

--trigger-off arg

Overrides configuration parameter thresholds.triggerOff.

--trigger-dead-time arg

Overrides configuration parameter thresholds.deadTime.

--ampl-max-time-window arg

Overrides configuration parameter thresholds.amplMaxTimeWindow.

--min-ampl-offset arg

Overrides configuration parameter thresholds.minAmplOffset.

--gap-tolerance arg

Overrides configuration parameter thresholds.maxGapLength.

--gap-interpolation arg

Overrides configuration parameter gapInterpolation.

--any-stream arg

Overrides configuration parameter useAllStreams.

--send-detections

Overrides configuration parameter sendDetections.

--extra-comments

Overrides configuration parameter extraPickComments.