armasuisse Swiss Federal Office of Topography swisstopo Determination of Tectonic Movements in the Swiss Alps using GNSS and Levelling E. Brockmann, D. Ineichen, U. Marti, S. Schaer, A. Schlatter

2 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Content Information sources for vertical tectonic movements -Swiss Permanent Network AGNES + analysis (10 years) -Levelling network + analysis (100 years) -Local ties (5-15 years) -GNSS-densification networks (16 years) Results and comparisons Next steps and conclusions

3 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Swiss Permanent Network AGNES 30 stations since 1998 operational (10-years anniversary) 50 km spacing GNSS since (20 antenna changed + but 10 double stations for reference frame monitoring) Analyzed by Bernese GNSS Software together with EUREF- and IGS stations (hourly + daily + weekly + annually)

4 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Multi-annual solution: Transformation parameters of weekly solutions - Weekly updated and SINEX+plots available: trafo-para. # sites rms based on rel. antenna PCV model + results not (yet) based on a reprocessing

5 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Height repeatability improvement due to vertical velocity estimation Swiss sites > 2 years observations 16 % improvement

6 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Example station: EPFL (Lausanne) 2.5 yr 2.2 yr 4.2 yr Equipment changes Relative velocity constraints ! Remark: “worst” case station (monumentation + many equipment changes)

7 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Combined multi-annual solutions: vertical velocities Reference: min. constraints for some IGS sites w.r.t. ITRF2005 at mean epoch of obs. downward movement rise 1 mm/yr

8 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Time series ZIMM-WTZR; comparisons -> ITRF2005 ZIMM: mm / yr WTZR: mm / yr ZIMM-WTZR: mm / yr -> EPN-densification (Dec. 08): ZIMM: mm / yr WTZR: mm / yr ZIMM-WTZR: mm / yr -> ITRF2008: ???

9 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling National height network 95 (LHN95) National Levelling network (LHN95): 4000 km, 1100 points Time span of data used: approx. 10’000 km line measurements

10 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Alpine Uplift determined from levelling Defined with zero vertical motion Levelling: Alps are rising 1.5 mm/yr

11 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Alpine Uplift model RCM04 Released 2004 Defined with zero vertical motion

12 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Comparison: GNSS / Model (Levelling) vertical velocities Re-scaled error ellipses from estimated formal rms Defined with zero vertical motion

13 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling GNSS vertical rates by region Re-scaled estimated formal rms

14 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Comparison: GNSS / Model (Levelling) vertical velocities (2) JUJO ZERM

15 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Comparison: GNSS / Model (Levelling) vertical velocities (3) 2 extreme alpine sites not considered (JUJO, ZERM) systematic discrepancy between GNSS and Model of roughly 1 mm/yr, which is a significant part (65-82%) of expected vertical movements min. (mm/yr) max. (mm/yr) difference (mm/yr) Model ind.-0.31STCX1.27ARDE1.58 GNSS ind.-1.10FHBB1.50MAR22.60 Model region-0.11north0.93Alps1.04 GNSS region-1.08north0.81Alps % %

16 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Local tie at Geostation Zimmerwald ZIM2 antenna and terrestrial target Local Tie (Sept. 2008): SLR – ZIMM – ZIM2 ZIM2 (1.5 yrs): mm/yr ZIMM (10 yrs): mm/yr Vertical velocities ZIMM/ZIM2 not relatively constrained +2.1 mm/yr CH-AarbergITRF mm/yr GNSS vertical velocities -1.2 mm/yr shift

17 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Local tie results: ZIMM - SLR 7 mm displacement5 mm rising of GPS horizontallyvertically (in 13 years)  local effect at the significance level to be detected with permanent networks;  overall movement is with +2.1 mm/yr (in ITRF05) significant ≈ 0.5 mm/yr ≈ 0.4 mm/yr Conclusion from local tie: Movement of top of the 9-meter mast

18 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Densification (200 LV95 sites; since 1989) 627 stations horizontally: homogeneous velocity results achieved (< 1mm/yr movements) vertically: possible problems due to antenna calibration inconsistencies Next campaign planned in > 21 years time span

19 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Conclusions Analysis of 10 years of permanent GNSS data verified an Alpine rising which was derived from 100 years repeated levelling (3 epochs). Due to Swiss permanent sites and the usage of IGS/EUREF sites, the movements w.r.t the stable Eurasian plate were determined, showing a rising of all Swiss sites. The rates from GNSS are bigger: Alps are rising 2.6 mm/yr (GNSS) compared to 1.5 mm/yr (levelling). Not all permanent AGNES sites are “tectonically” suited sites; local effects of “class-A” / double stations are monitored with local ties. Additional info (GNSS densification campaign 2010, local tie results of additional 9 double stations, homogeneous reprocessing) will improve the results and its interpretation.

20 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Thanks for your attention downward movement rise 1 mm/yr

21 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Multi-annual solution: statistics Descriptionvalue Total number of L3-observations (sampl. 180 s) 839'170'883 Total number of observation files 273'612 Total number of stations / station setups 228 Total number of explicit parameters (coord. + vel.) 1'368 Total number of implicit parameters (tropo + ambig.) 7'688'118 Total number of adjusted parameters 7'689'486 Degree of freedom (DOF) A posteriori RMS of unit weight m Chi**2/DOF 1.83 *2*3 results not based on a reprocessing analysis model as consistent as possible (rel. antenna model also after GPS-week 1400 [parallel solutions]) remarks

22 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Loose relative velocity constraining Constraint of 1.0E-5 m: several velocity estimates per stationHorizontal velocities EPFL

23 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Heavy relative velocity constraining Constraint of 1.0E-6 m: 1 single velocity estimate per stationHorizontal velocities EPFL

24 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Densification: horizontal (GPS campaigns) + vertical velocities (levelling) Combined 3D velocity field interpolated in a 10 x 10 km grid by ALSC. The colour map gives the velocities in [mm/yr], the gray scale of the arrows gives the inclination of the velocity vectors

25 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Densification: horizontal velocities

26 Swiss Federal Office of Topography swisstopo Tectonic Movements in the Swiss Alps using GNSS + Levelling Next steps Taken into account local tie results (possible at ~ 10 tectonically stable “class A” stations or double GNSS stations) Densification Campaign 2010 will give additional information Reprocessing of all AGNES sites (homogeneous network and analysis models) Combination with other geological / seismic information