INTERREG
project preparation meeting
July 10-11, 2014
Trieste, Italy
The RSNI Seismic Network
Laboratory of seismology, DISTAV University of Genoa (Italy)
www.distav.unige.it/rsni
RSNI STAFF : Spallarossa D., Barani S., De Ferrari R., Ferretti G., Pasta M., Pavan M.,
Scafidi D., Turino C. (E-mail: daniele@dipteris.unige.it)
RSNI seismic stations
RSNI
Regional Sesismic Network of
North Western Italy
Team: 5 person
Stations: BB
and
Episensor
(Nanometric Trillium
40 s)
Stations:
realtime
trasmission
(Nanometric Taurus)
Seismic stations connected in REAL-TIME to
the RSNI datacenter (Genoa)
RT data exchange:
SeedLink and Nanometric
softwares
RSNI Data Processing Center
The main aims of the RSNI Data Processing Centre (DPC) are:
• Real-time monitoring of the seismicity of the South-Western Alps and Northern Apennines.
(location, magnitude estimate, shake maps)
• Daily manual revision of the detected seismic events.
• Dissemination of seismic data (location and ground motion parameters, waveforms) by WEB interface,
E-Mail and SMS.
Event detection:
Nanometric software
Event detection:
Ml < 0.5
Automatic Event
Location:
RSNI-Picker
RSNI-Picker
Automatic picking and location procedure
• The RSNI-Picker is represented by an iterative procedure consisting of different stages which
calculate P- and S-arrival times and also earthquake location
• P- and S-wave arrival times are obtained by calculating the AIC function from filtered seismogram
• The AIC-based module is driven (i.e.: selecting the proper part of the signal) by the use of a-priori
information derived from the characteristic of the signal (i.e.: envelope function) or from the results
of the previous iteration (i.e earthquake location)
• RSNI-Picker produce consistent arrival times, quality class assignment to automatic readings, and
remove gross errors and false picks.
The performance of the picker has been tested using three different data
set: NW Italy, California and New Zeland
Performances of the RSNI-Picker
RSNI dataset (Italy)
• Picking hit-rate (e.g., the ratio between number of common automatic and manual
readings and all available manual ones): 80% for P and 62% for S.
• The picker identified 82% of automatic readings with differences lower than 0.1 s and
only 0.5 % of readings with differences greater than 0.5 s
• For S-phases the picker provided 42.0 % of readings with differences lower than 0.1s,
70% with differences lower than 0.2 s and 10 % with differences greater than 0.5 s,
Performances of the RSNI-Picker
Earthquake locations (RSNI database - Manual vs. Automatic
picking)
Performances of the RSNI-Picker
SCEDC dataset (California)
Performances of the RSNI-Picker
GeoNet dataset (New Zealand)
Performances of the RSNI-Picker
Seismic tomography
The analysis of the differences between
tomographic results, in terms of absolute P
wave velocities (km s-1) obtained using the
automatic pickings and the manual ones,
shows that the 95 % of the differences are
less than 0.5 km s-1. The same analysis in
terms of VP/VS ratio shows that the 95 %
of the differences are less than 0.08.
Moreover, the greater differences are
confined at the border of the model, while
only smaller differences are confined inside
the study area of the Trentino region.
CONCLUSIONS:
- Our automatic picking procedure performs
well with this very heterogeneous dataset.
- The number and the quality of automatic P
and S onsets are not far from the manual
ones.
- The small differences observed among
tomographic results permit to demonstrate
that our automatic picking engine can be
used for reprocessing large amount of
seismic recordings also with the aim of
performing a local tomographic study.
Items for draft proposal
 Calibration of the RSNI picker (Turino et al., 2010 – Spallarossa et al.,
submitted to SRL) for its application in Central Europe
 Comparison among performances of automatic pickers and automatic location
procedures
 Producing shakemaps in Central Europe: calibration of relationships between
Peak Ground Acceleration, Peak Ground Velocity and Modified Mercalli Intensity
for producing Instrumental Intensity map by Shakemap© code
 Calibration of an Ml scale in Central Europe