This page describes how to improve the monitoring of local earthquakes by configuring scautoloc and scautopick

The goal is to

Side effect could be that we will no more detect teleseismic events but, if this is one of the tasks of our monitoring activities we can define a secondary pipeline with specific configuration (see secondary pipeline page)

scautopick configuration: 

KEY_VERSION='2.5'
 DETEC_STREAM='HH'
 DETEC_LOCID=''
 DETEC_FILTER='RMHP(10)>>BW(4,5,20)>>STALTA(1.0,30)'
 TRIG_ON='4'
 TRIG_OFF='1.5'

The most relevant changes are:

These parameters can be assigned to the stations in different ways:

For the case of netwok using different primary streams (e.g. some stations with HH and some with EH) the preferred solution would be to define two different profiles and assign the proper one to each station by using import_dlsv -p "trunk:profile_name" In case of using profile and if the network has different types of primary streams, different profiles should be created, For the same case it is complicated to use the .seiscomp3/scautopick.cfg file because it will require to assign on detection_stream for each station.

* changes in .seiscomp3/scautopick.cfg 

 timeCorrection = 0.0 # a short STA time-window will not require an arbitrary time shift
 initTime = 20  # 
 thresholds.maxGapLength = 0.5 # this changes fits with the lenght of the minimum expected gap when using 120 or 200 sps
 thresholds.amplMaxTimeWindow = 2 # after filtering between 4 and 20Hz we do not need a long time-window and this speed-up the release of the pick
 thresholds.deadTime = 0 # to prevent the blindness of the picker after releasing a pick. 

autoloc.dynamicPickThresholdInterval = 60 # this number defines the threshold at which scautoloc will start discarding picks for a certain station (in this case after 10 picks of similar SNR amplitude withing 60s) 
autoloc.maxResidual = 3.0 # reduce the max allowed residual for each pick, 3s is reasonable at local scale and could prevent to mix P-phase with some S-phase detections from far stations with small P onset
autoloc.thresholdXXL = 10000000. # disable XXL feature
autoloc.minPhaseCount = 5
eventAssociation.minimumDefiningPhases = 5
autoloc.grid = @CONFIGDIR@/your_local_grid.conf  # see below (@CONFIGDIR@/ means that the grid file will be located in folder .seiscomp3
autoloc.amplTypeAbs = "snr" # faster than for the case of mb and more realistic for local purposes.

According to the documentation and to some tests it is reasonable to keep the number of node as small as possible because this correlates with the computation time of scautoloc. When the purpose is to provide just local monitoring (and the above trigger filter will prevent to get picks for teleseismic pick arrival) it makes sense to use a dense, limited in space grid. A simple script to create the grid can be found here: http://www.seiscomp3.org//recipes/local-monitoring/make_grid.sh

For the case of Switzerland we defined a .1 spaced rectangle with latitude ranging between 5 and 12 degrees and longitude ranging between 45 and 49: 

45.0 5.0 10 .2 20.0 5  #for the case of Switzerland

surrounded by a less dense rectangle ( (-5< longitude < 21, 35 < latitude <59 ) that covers almost the entire Europe. 

   59.0 21.0 10.0 1 180.0 6 #for the case of Europe

Please note that Switzerland has only shallow seismicity so it is not necessary to add multiple layers.
Figure 1: Example of a grid as set up for monitoring Switzerland

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