Nanoseismic Monitoring by Seismic Navigation System (SNS) M. Joswig Institut für Geophysik, Universität Stuttgart, Germany data logger 3-D 1-D
Be Fast ! Site selection with initial noise survey worth to stay here ?
Be Fast ! Site selection with initial noise survey seismometerdata loggerWLAN field notebook with WLAN min after arrival sonogram, i.e. detectable signal energy noise variance power spectral density matrixnoise mean scaled, filtered seismogram
Be Flexible ! Array installation, survey of geometry okay, let‘s bring it up ! min after arrival
Be Flexible ! ~100m Z Z Z 3c Done min after arrival ! (Lat, Lon, h ) (x 1, y 1, h 1 ) (x 2, y 2, h 2 ) (x 3, y 3, h 3 ) Tripartite, Equilateral Array with 3-Comp Center Station
Details: WLAN, Data Logger, Breakout Box, Seismometers, Cable Drums
Details: Laser Distance Meter, GPS incl. Compass, Tilt Meter, Tripod
Be Independent ! Process events with just local means any results right now ?
Be Independent ! Process events with just local means one SNS gives you all - distance by t P - t S - direction by array beam - approx. depth and halfspace v P by hyperbola and incidence angle - magnitude by WA-simulation SNS
Be Sensitive ! Process events down to the ground noise how small is small ?
Be Sensitive !... too weak to process ? seismogram zoom window of 14 sec array 3comp map zoom map depth profile
Be Sensitive !... just a challenge to HypoLine ! adjust phases by sonogramsadapt layer model get depth get epicenter
increase depth hyperbola grow circles shrink Search Solution Space bv Variation of Hypolines
increase depth
? circles vanish!
? increase depth circles vanish!
optimum depth increase vP hyperbola grow circles grow spread increases
increase vP
optimum vP optimum depth minimum spread
Be Sensitive !... just a challenge to HypoLine ! confirm P beamconfirm S beam
Be Sensitive !... just a challenge to HypoLine ! get magnitude M l -2.1 in 1.4 km !... and the result is
Burete Fortuna3 Example: Monitoring Threshold and Noise Samples (20 sec, night time) Distance correction for M l Events per night:
Be Portable ! Access remote, quiet sites off any roads it‘s getting better...
... in fact, ultra-portable ! cable drums data logger WLAN seismometers GPS, laser dist meter field notebook tripod
...and finally, the team.