2142-Presentation. Advanced Conference on Seismic Risk Mitigation and Sustainable Development May Asi-Sisma Presentations

Transcription

1 2142-Presentaton Advanced Conference on Sesmc Rsk Mtgaton and Sustanable Development May 2010 As-Ssma Presentatons CANNIZZARO Letza, Barzagh R. and Borgh A. DIIAR - Poltecnco d Mlano ITALY Italan Insttute of Oceanography and Appled Geophyscs c/o Poltecnco d Mlano ITALY

2 SISMA Project The role of GNSS n SISMA project Prof. Rccardo Barzagh (1), Dr. Alessandra Borgh (2), Dr. Letza Cannzzaro (1) (1) DIIAR - Poltecnco d Mlano (2) Italan Insttute of Oceanography and Appled Geophyscs c/o Poltecnco d Mlano Sesmc Rsk Mtgaton & Sustanable Development The Abdus Salam Internatonal Centre for Theoretcal Physcs 14 May 2010, Mramare - Treste

3 Outlne Lst of present GNSS products nsde SISMA project Descrpton of the algorthms of GNSS SISMA Software appled at regonal scale Example of GNSS product at regonal scale Descrpton of the algorthms of GNSS SISMA Software appled at local scale Example of GNSS product at local scale Conclusons

4 The SISMA products of the GNSS At Regonal scale: Maps of crustal stran and stran-rate tensors, whch provde a descrpton of the tectonc process over the Italan regon At Local scale: Maps of crustal stran and stran-rate tensors, whch provde a descrpton of the fault stran accumulaton

5 The SISMA products of the GNSS All maps are derved by GNSS coordnate tme seres analyss At Regonal scale: Daly data collected by several GPS Permanent Staton Networks are analysed. The GPS statons cover the Italan terrtory At Local scale: Perodcal data collected by means of GPS campagns are analysed. The GPS vertces are located for montorng fault system purpose

6 The SISMA software for GNSS tme seres analyss At Regonal scale: gnss_naz s the developed automatc software for GNSS coordnate tme seres analyss comng from GPS permanent statons At Local scale: gnss_loc s the developed automatc software for GNSS coordnate tme seres comng from GPS local campagns.

7 The SISMA software for GNSS tme seres analyss Flow dagram of GNSS data analyss Data set: coordnate tme seres of GNSS statons Automatc software for tme seres analyss Velocty dsplacements of GNSS statons Automatc software for stran/stran rate estmaton GIS maps The algorthms of regonal GNSS tme seres analyss are qute dfferent from those of local GNSS tme seres. The man characterstcs wll be brefly descrbed

8 The regonal GPS network ~ 80 GNSS Permanent Statons belongng to several Networks set up for qute dfferent purposes Freely avalable on ftp stes Collected data must be at least three years long: t s smple to add or remove other statons

9 GPS data processng Insde SISMA project the GPS data processng software used for regonal analyss s NDA Professonal, whch was developed by Gallean Plus. NDA Professonal computes automatcally coordnates tme seres for the network statons. At the moment the avalable tme span of the GNSS coordnate tme seres are four years long, startng from 2006

10 The steps of the automatc gnss_naz software 1 Step: removal of outlers and known dscontnutes due to: techncal equpment changes (.e. GNSS antennas) not straght algnment of Reference Frames transformaton parameters co-sesmc effect 2 Step: lnear and perodc parameter estmatons by least square adjustment 3 Step: generalsed KPSS test on resduals for assessment of statonary behavour 4 Step: account of coordnate tme seres correlatons Statonary resduals Estmate of the Emprcal Covarance Functon Not statonary resduals smplfed Whte Nose + Flcker Nose model (Wllams, S.D.P., 2003) 5 Step: lnear and perodc parameter re-estmatons by least square adjustment applyng the correct stochastc model

11 The steps of the automatc gnss_naz software 1 Step: removal of outlers and known dscontnutes due to: techncal equpment changes (.e. GNSS antennas) not straght algnment of Reference Frames transformaton parameters co-sesmc effect 2 Step: lnear and perodc parameter estmatons by least square adjustment 3 Step: generalsed KPSS test on resduals for assessment of statonary behavour 4 Step: account of coordnate tme seres correlatons Statonary resduals Estmate of the Emprcal Covarance Functon Not statonary resduals smplfed Whte Nose + Flcker Nose model (Wllams, S.D.P., 2003) 5 Step: lnear and perodc parameter re-estmatons by least square adjustment applyng the correct stochastc model

12 Functonal model Stochastc model The determnstc model for GPS tme seres analyss y C = a + bt = dag + m ( ) yy C yy 0 [ ( ) ( ) ] A m cos ω m t + Bm sen ω m t + m = 0 j k = 1 Where: a s the ntercept b s the dsplacement rate due to plate tectonc moton A m, B m are cosne and sne ampltudes at frequency f m =2πω m. H(t -T k ) s the Heavsde functon, whch equals 1 for t > T k g k are the ampltude of any offset due to co-sesmc events, Reference System or GPS Antenna or Recever changes ε s the nose component H ( t T k ) g k + ε The frequences f m and ther maxmum number m 0 are chosen among the most sgnfcant Lomb s perodogram peaks.

13 The stochastc model for GPS tme seres analyss y = a + bt + m 0 [ ( ) ( ) ] A m cos ω m t + Bm sen ω m t + m = 0 j k = 1 H ( t T k ) g k + ε Statonary doman C = mod ( ˆ ) yy C yy Resduals m 2 Statonary test: passed Emprcal covarance Emprcal covarance functon Not Statonary doman C yy 2 w = σ I +σ 2 f Q f (Wllams, S.D.P., 2003)

14 Fnal parameter estmates y = a + bt + m 0 [ ( ) ( ) ] A m cos ω m t + Bm sen ω m t + j H ( t T k ) g k + ε C m = 0 ( ˆ ) 2 2 yy = mod C yy OR C yy = σ w I +σ f Q f k = 1 Stochastc model North East Up AMUR GPS Permanent staton Velocty estmate under n-correlaton hypothess / / / Velocty estmate by ECF / / /- 0.59

15 Remarks on gnss_naz software 1. The software s automatc and the network can be modfed easly 2. The software attempts to combne the present day scentfc knowledge on GPS tme seres analyss comng from dfferent approaches: The software s ntended to lookng for proper functonal model Nkolads, R., Observaton of Geodetc and Sesmc Deformaton wth the Global Postonng System, PhD thess. Unversty of Calforna, San Dego Amr-Smkooe A.R., Tberus C.C.J.M., Teunssen P.J.G. (2007), Assessment of nose n GPS coordnate tme seres: Methodology and results, Journal of geophyscal research, 112, B The software s ntended to lookng for proper stochastc model Wllams S.D.P. (2003), The effect of coloured nose on the uncertantes of rates estmated from geodetc tme seres, Journal of Geodesy, 76, Cannzzaro L. (2008), Analyss of temporal correlatons n GPS tme seres: comparson between dfferent methods at dfferent space scale, PhD Thess n Geodesy and Geomatcs, Poltecnco d Mlano 3. Further mprovements are, of course, necessary: e.g. the post-sesmc phase n GNSS tme seres must be developed and further nvestgated

16 The Regonal scale: the GNSS fnal product A prelmnary result Zonazone ssmogenetca ZS9 - App.2 al rapporto conclusvo, C. Melett, G. Valse et al, marzo INGV

17 Other GNSS results Predcted (coloured arrows) vs GPS veloctes (black arrows). The percent represents the amount of Afrca Eurasa convergence transmtted through the Calabran subducton. Classfcaton of the geophyscal models obtaned wth the χ 2 analyss. The per cent ndcates the percentage of the Afrca Eurasa convergence transmtted to the Eurasan plate through the Calabran subducton zone. SPLENDORE, R., MAROTTA, A. M., BARZAGHI, R., BORGHI, A. & CANNIZZARO, L., Block model versus thermo-mechancal model: new nsghts on the present-day regonal deformaton n the surroundngs of the Calabran Arc. Geologcal Socety, London, Specal Publcatons, 332,

18 The local GNSS scale The am of GNSS technque nsde the project was also: to mprove the knowledge of local faults mechansms by means of local GNSS campagns to provde GNSS data for GFIM partners An automatc procedure to analyse GNSS local campagn data was developed The local campagns requre: a dense GPS network n a qute small area a careful dstrbuton of the GNSS stes n the studed area a sold and expensve monumentaton of the GNSS stes a sgnfcant observaton wndow Three test areas: the GNSS network has been already monumented some GNSS campagns have been already done three dfferent earthquake cycle: nter-sesmc, pre-sesmc and post-sesmc phases

19 The test areas

20 The avalable campagns Area Tot. Colforto 5 Pollno 6 Gemona del Frul 5 SISMA campagns

21 The steps of the automatc gnss_loc software 1 Step: estmaton of GNSS solutons: GAMIT/GLOBK and NDA professonal 2 Step: lnear parameter estmatons (velocty dsplacements) by least square adjustment 3 Step: Common Mode Error reducton (Wdownsk et al., 1997) 4 Step: unque soluton 5 Step: velocty re-estmatons by least square adjustment Crtcal pont It s dffcult to take nto account tme seres dscontnutes (e.g. antenna change, Reference Frame resdual, co-sesmc event) SISMA campagns

22 Some results: GPS for GFIM support n Pollno area GPS veloctes (black arrows) n the Eurasan reference frame (defned by the geodetc plate knematc model APKIM2005) and relatve 1 confdence error ellpses vs. model veloctes (red arrows) Slp rate over the Castrovllar fault from the nverson of GPS veloctes. Mean stran-rates from GPS surveyng, at the ten GPS stes n the Pollno Range. The thn grey lnes ndcate the Castrovllar fault scarps (Cnt et al. 2002)

23 Conclusons The present GNSS contrbuton nsde SISMA project conssts n: Provdng an automatc software that allows a contnuous updatng of GNSS deformaton maps comng from Contnuous GPS network analyss. Provdng an automatc software that allows the analyss of GNSS data for local faults montorng V3 At the moment we are studyng and lookng for geodetc ndcators that hghlght geodetc anomalous behavours that could be the used to ntegrate sesmc results and geodesy nformaton. Thanks for your attenton.