Precise Levelling Campaigns at Olkiluoto in 2010 and 2011

Working Report 2012-64 Precise Levelling Campaigns at Olkiluoto in 2010 and 2011 Veikko Saaranen Paavo Rouhiainen Heli Suurmäki Finnish Geodetic Institute May 2013 Working Reports contain information on work in progress or pending completion. The conclusions and viewpoints presented in the report are those of author(s) and do not necessarily coincide with those of Posiva.

PRECISE LEVELLING CAMPAIGNS AT OLKILUOTO IN 2010 AND 2011 ABSTRACT The Finnish Geodetic Institute established the Olkiluoto GPS network in 1994 and started precise levelling survey in autumn 2003. The first levelling survey included the GPS network and the line Lapijoki-Olkiluoto, which connects Olkiluoto to precise levelling network in Lapijoki and gives information about the movement of the Olkiluoto area relative to the continent. The line Lapijoki-Olkiluoto was decided to survey every fourth year and the GPS network every two years. New benchmarks have been added to the levelling network to give more precise information for the area with observed abnormal deformation. Height change of benchmarks GPS6 and GPS9 was more than one millimetre relative to other benchmarks between 2003 and 2005. New levelling loops were established and levelled onto the research facility ONKALO and the low and intermediate level waste (VLJ) repository in 2006. The levelling period of these micro loops was decided to be one year. In 2007 it was noticed that in the loop ONKALO benchmark 06220 was one millimetre higher than a year ago. Two new benchmarks were established in 2008 near 06220. Measurements in 2008 and 2009 supported earlier results and benchmark 06220 was still rising. The latest measurements in 2010 and 2011 show that this movement does not exist at the moment. Actually this benchmark is at a lower level relative to fixed benchmark 03216 than it was in 2009. In loop OLKIA benchmarks 03216, GPS6 and GPS7 have the same uplift rate between 2009 and 2011. GPS13 has uplifted 0.80 mm and other benchmarks 0.35-0.65 mm relative to 03216. The problem area over the Olkiluoto strait was found out in 2007. A height difference of benchmark interval 03208-03211 changed 1.9 mm between 2003 and 2007. Since 2007 the Olkiluoto strait line has been measured every year. In 2008 the difference was only 1.5 mm. The latest measurements show that this interval is not active at the moment. The height difference in 2011 was close to the result of 2007. The comparison between 2010 and 2011 measurements shows two new unstable benchmark intervals. Those are benchmark interval GPS9-06213 in the VLJ loop and benchmark interval 04005-03211 in the Olkiluoto strait line. The Lapijoki-Olkiluoto line measurements in 2003, 2007 and 2011 show insignificant elevation change between the mainland and Olkiluoto island since 2003. The new GPS stations GPS16, GPS17, GPS18 and GPS19 were established and connected to a levelling network in 2011. Keywords: Deformation of bedrock, precise levelling, vertical control

TARKKAVAAITUSKAMPANJAT OLKILUODOSSA VUOSINA 2010 JA 2011 TIIVISTELMÄ Geodeettinen laitos perusti Olkiluodon GPS-verkon vuonna 1994 ja suoritti ensimmäiset tarkkavaaitukset Olkiluodon alueella vuoden 2003 syksyllä. Tällöin vaaittiin GPS-verkko ja vaaituslinja Lapijoki-Olkiluoto. Linja liittää Olkiluodon alueen tarkkavaaitusverkkoon ja mahdollistaa Olkiluodon saaren ja mantereen välisen muutoksen seurannan. Mittaukset linjalla Lapijoki-Olkiluoto päätettiin suorittaa joka neljäs vuosi ja GPS-verkossa joka toinen vuosi. Tutkimusaluetta on laajennettu mittaustulosten perusteella. Vuonna 2005 havaittiin, että GPS6:n ja GPS9:n korkeusero muihin pisteisiin nähden oli kahdessa vuodessa muuttunut yhden millimetrin. Syksyllä 2006 ONKALOn ja VLJ-luolan yläpuolelle perustettiin seitsemän ja viiden pisteen mikrosilmukat. Nämä vaaitussilmukat on mitattu vuosittain. Vuonna 2007 havaittiin, että ONKALON yläpuolella sijaitseva kiintopiste 06220 oli vuodessa noussut lähes millimetrin ympäristöönsä verrattuna. Syksyllä 2008 sen lähistölle perustettiin kaksi uutta pistettä. Vuosien 2008 ja 2009 mittausten pohjalta todettiin, että 06220 oli edelleen hieman noussut ympäristöönsä nähden. Uudet mittaukset 2010 ja 2011 osoittavat, että kiintopisteen 06220 liike ei ole jatkunut, vaan uusissa mittauksissa pisteen korkeus on laskenut suhteessa kiinnitettyyn pisteeseen 03216. Vuonna 2011 Olkiluodon saaren silmukassa OLKIA ainoastaan GPS6 ja GPS7 olivat samalla korkeudella kiinnitettyyn pisteeseen 03216 nähden kuin vuonna 2009. Muut pisteet olivat korkeammalla tasolla. Eniten oli noussut GPS13 0.80 mm. Muiden pisteiden nousu oli 0.35-0.65 mm. Vuoden 2007 mittaus Lapijoki-Olkiluoto linjalla toi esille uuden muutosalueen. Kiintopistevälin 03208-03211 korkeusero oli muuttunut 1.9 mm neljässä vuodessa. Väli otettiin tarkemman tutkimuksen kohteeksi ja sen vuosittaiset mittaukset aloitettiin. Vuonna 2008 korkeusero oli osittain palautunut ja oli enää 1.5 mm. Uusimmat mittaukset eivät ole osoittaneet merkittävää muutosta. Vuoden 2011 tulos oli lähes sama kuin vuonna 2007. Vuosien 2010 ja 2011 mittauksien tuloksia vertailemalla löytyi VLJ-silmukasta merkittävä muutos kiintopistevälillä GPS9-06213. Olkiluodon salmen vaaituslinjan väli 04005-03211 on myös muuttunut merkittävästi. Lapijoki-Olkiluoto väli on mitattu 2003, 2007 ja 2011. Mittaustulosten mukaan muutokset Olkiluodon saaren ja mantereen välillä ovat pieniä. Vuoden 2011 aikana perustettiin ja liitettiin vaaitusverkkoon uudet GPS-asemat GPS16, GPS17, GPS18 ja GPS19. Avainsanat: Kallioperän deformaatio, tarkkavaaitus, korkeuskontrolli

1 TABLE OF CONTENTS ABSTRACT TIIVISTELMÄ 1 INTRODUCTION... 3 2 LEVELLING IN 2010 AND 2011... 5 3 RESULTS IN 2010 AND 2011... 7 3.1 Height differences and adjustment result for 2010... 7 3.2 Height differences and adjustment result for 2011... 9 4 COMPARISON WITH PREVIOUS LEVELLINGS... 17 4.1 Standard deviations for the comparisons between levelling... 17 4.2 Lapijoki-Olkiluoto... 18 4.3 Olkiluoto strait... 19 4.4 OLKIA and OLKIB... 21 4.5 Micro loop ONKALO... 26 4.6 Micro Loop VLJ... 30 4.7 GPS antenna platform measurements... 34 5 FUTURE PLANS... 37 6 SUMMARY... 39 7 REFERENCES... 41 APPENDIX I, OBSERVATION IN 2010 AND 2011... 43 APPENDIX II, POSIVA LINE PAPERS 2010-2011... 369

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3 1 INTRODUCTION The Finnish Geodetic Institute started the precise levelling in order to monitor vertical movements at the Olkiluoto area in autumn 2003. The GPS network and the Lapijoki- Olkiluoto line between Olkiluoto island and continent were measured during the first observation year. The levelling interval of the Lapijoki-Olkiluoto line was decided to be four years and of the GPS network two years. The new levelling loops were established and levelled onto the research facility ONKALO and the low and intermediate level waste (VLJ) repository in 2006. The levelling period of these micro loops was decided to be one year. The Olkiluoto strait line has been measured every year since 2007. The new GPS stations GPS16, GPS17, GPS18 and GPS19 were established and connected to a levelling network in 2011. This report treats the levelling campaigns in the autumns 2010 and 2011 and the comparison with the previous campaigns (Lehmuskoski 2004, 2006, 2008 and 2010). The fieldwork and the calculations were carried out by the same method that was used in the Third Levelling of Finland (Lehmuskoski et al. 2010).

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5 2 LEVELLING IN 2010 AND 2011 The precise levelling campaign in 2010 includes the loops above ONKALO and VLJ repository and the Olkiluoto strait line. All the levelling lines were measured in 2011. Their levelling dates are shown in Table 1. Table 1. Levelling lines and observation dates. Loop, GPS pillar or line Date ONKALO 28.-29.9.2010 and 30.-31.8.2011 VLJ 30.9.2010 and 29.-30.8.2011 Olkiluoto strait 29.9.-1.10.2010 and 29.9.2011 Lapijoki-Olkiluoto 3.10.-12.10.2011 OLKI B 6.-7.9.2011 and 21.9.2011 OLKIA and GPS Stations 31.8.-28.9.2011 Posiva Oy employed the assisting personnel for the levelling campaigns. The crew and the used instruments are given in Table 2. Table 2. Field crew and instruments. Surveyors Paavo Rouhiainen (2010 and 2011), Veikko Saaranen (2011) Levelling expedition 2010 Simo Muttilainen, Jari-Pekka Mäntylä, Teppo Levelling expedition 2011 Peltola and Jarno Reijonsaari Margus Erstu, Jevgeni Frid, Sami Lehtonen, Samu Maijala and Simo Muttilainen Levelling instrument Zeiss DiNi12, number 320243 Rod pair (3 metres) Zeiss Nedo LD13, numbers 13926 and 14092 Rod (1 metre) Zeiss Nedo LD11, number 11640 Thermometer Rod bases Tripods Distance meter Umbrella Car Personal Navigator Fluke 54 II Turtles and spikes Wild GST 20 normal, Zeiss extendable Rollfix Alexo Toyota Hiace, UXY-346 Garmin etrex The description of the levelling is presented in Lehmuskoski 2006, Chapter 3. In Appendix I there is in the chronological order information about every benchmark interval measured in 2010-2011. One page represents one benchmark interval and one levelling direction. The upper part of the page shows time, crew, instrumentation, road type and weather. The lower part gives observations and environmental data for every step. At the end of the observation file there are an uncorrected height difference, distance between benchmarks and possible remarks.

Figure 1. Levelling network in the 2011 adjustment. The Lapijoki-Olkiluoto line (red line) was measured in 2011. Benchmark 03216 was used as a fixed benchmark. In the 2010 adjustment three separate networks had fixed values from the 2011 adjustment. 6

7 3 RESULTS IN 2010 AND 2011 An adjustment program is Local X- Positioning system. An adjustment method is a constrained net. The weight of each observation is inversely proportional to the distance of the benchmark interval. A priori accuracy in the adjustment has been 1.0 mm/ km and in a statistical testing reference variance 1.0 (unitless) was used. Observations in the adjustments are from line papers which are presented in Appendix 2. In line papers, the height difference is mean of forward and back measurements. Some intervals belonged to more than one line. In this case, all height differences were in the adjustment. The height differences were corrected for rod meter, tidal deformation and refraction before adjustment. We used the Zeiss Nedo LD13 bar code invar rods with an aluminum frame for the ordinary precise levelling. Zeiss Nedo LD11 invar rod with an aluminum frame was used when the elevations of the GPS antenna platforms were levelled. The rod calibrations were carried out before and after the field season using the FGI vertical rod comparator (Takalo 1999, Takalo and Rouhiainen 2002). The corrected value for the levelling epoch was obtained by linear interpolation. During the levelling an air temperature and its difference between 2.5 m and 0.5 m above the ground were registered with a Fluke 54 II thermometer at one minute intervals. Refraction correction was computed with the Kukkamäki formula (Hytönen 1967) and tidal correction with the formulas of Heikkinen (1978). 3.1 Height differences and adjustment result for 2010 There are 21 height differences and 22 benchmarks in the adjustment of the 2010 measurements (Tables 3 and 4). The observations were performed in three lines which are ONKALO (on10), VLJ (vl10) and Olkiluoto strait (st10). For every line one fixed benchmark was used. Benchmark 03216 was fixed for the adjustment of the ONKALO loop at its N60 elevation 9.522538 m derived from the 2003 campaign. Starting values for VLJ and Olkiluoto Strait are from the 2011 adjustment. In Loop VLJ starting value is 9.767028 m at benchmark GPS9A and in Olkiluoto Strait it is 1.541372 m at benchmark 03211. The accuracy for the 2010 measurements of the adjustment is 0.27 mm/ km. The average precision of the adjusted heights is 0.16 mm. The precisions presented in Tables 4 and 6 are dependent on the location of the fixed benchmark in the network.

8 Table 3. Observations in the 2010 adjustment. Columns are benchmarks (from, to), line, distance (km), observation, adjustment correction and adjusted height difference. 03216 06221 on10 0.719 5.21773 0.17 5.217895 06221 08201 on10 0.034-4.03749 0.01-4.037482 08201 06220 on10 0.069-0.72794 0.02-0.727924 06220 08202 on10 0.050-0.42790 0.01-0.427889 08202 06219 on10 0.082 0.02409 0.02 0.024109 06219 06218 on10 0.390 0.41998 0.09 0.420070 06218 06217 on10 0.344-2.44489 0.08-2.444811 06217 10301 on10 0.197 3.28582 0.05 3.285865 10301 03219 on10 0.795-0.28977 0.18-0.289587 03219 03216 on10 0.018-1.02025 0.00-1.020246 03211 04005 st10 0.039 0.90800 0.00 0.908000 04005 08204 st10 0.222-0.27383 0.00-0.273830 08204 08203 st10 0.395 3.91012 0.00 3.910120 08203 03208 st10 0.127 3.62797 0.00 3.627970 03208 04004 st10 0.052 0.27920 0.00 0.279200 GPS9A GPS9B vl10 0.014-0.52439 0.00-0.524389 GPS9B 06213 vl10 0.075 1.36828 0.01 1.368288 06213 06214 vl10 0.126-0.61952 0.01-0.619507 06214 06215 vl10 0.077 1.08330 0.01 1.083308 06215 06216 vl10 0.122-3.40033 0.01-3.400317 06216 GPS9A vl10 0.242 2.09259 0.03 2.092616

9 Table 4. Benchmarks in the 2010 adjustment and their KKJ coordinates in zone 27 and geographical coordinates longitude ( ) and latitude ( ), height (m) and precision (mm) 03208 6802779.0 3205831.0 21.517275 61.222509 9.713632 0.24 03211 6802314.0 3206363.0 21.527854 61.218755 1.541372 Fixed 03216 6804168.0 3204117.0 21.483343 61.233624 9.522538 Fixed 03219 6804154.0 3204109.0 21.483216 61.233493 10.542784 0.04 04004 6802736.0 3205815.0 21.517045 61.222113 9.992832 0.25 04005 6802334.0 3206392.0 21.528361 61.218955 2.449372 0.05 06213 6805403.0 3201332.0 21.429778 61.242539 10.610927 0.08 06214 6805445.0 3201428.0 21.431491 61.242987 9.991421 0.10 06215 6805398.0 3201444.0 21.431862 61.242580 11.074729 0.11 06216 6805469.0 3201501.0 21.432806 61.243257 7.674412 0.11 06217 6804590.0 3203605.0 21.473191 61.237006 7.546506 0.22 06218 6804655.0 3203890.0 21.478371 61.237803 9.991317 0.22 06219 6804478.0 3204044.0 21.481503 61.236338 9.571247 0.22 06220 6804432.0 3203953.0 21.479889 61.235858 9.975027 0.21 06221 6804349.0 3203994.0 21.480779 61.235148 14.740433 0.20 08201 6804380.0 3203998.0 21.480805 61.235428 10.702951 0.20 08202 6804442.0 3203990.0 21.480559 61.235976 9.547138 0.21 08203 6802685.0 3205930.0 21.519255 61.221744 6.085662 0.22 08204 6802470.0 3206180.0 21.524222 61.220011 2.175542 0.14 10301 6804536.0 3203479.0 21.470941 61.236428 10.832371 0.21 GPS9A 6805475.0 3201335.0 21.429719 61.243184 9.767028 Fixed GPS9B 6805472.0 3201321.0 21.429465 61.243147 9.242639 0.03 3.2 Height differences and adjustment result for 2011 There are 122 height differences and 87 benchmarks in the adjustment of the 2011 measurements (Tables 5 and 6). The N60 elevation 9.522538 m derived in 03216 from the 2003 campaign was fixed in the adjustment. The observation data include lines Lapijoki-Olkiluoto (LAPI), ONKALO (on11), VLJ (vl11) and Olkiluoto strait (st11). Loop OLKIA and levellings for GPS stations were included in lines 11gp, GP17, GP18, GP19, GP6A, GP6S, GP9S, GPS2, GPS4, GPS7 and GPS8. The accuracy for the 2011 measurements of the adjustment is 0.23 mm/ km. The average precision of the adjusted heights is 0.37 mm. The levelling was focused on a bolt A on the GPS antenna platform. To compute height observation to an antenna platform level, height of the bolt +19.912 mm has to correct from an observation.

10 Table 5. Observations in the 2011 adjustment. Columns are benchmarks, line, observation, adjustment correction and adjusted height difference. * = Measured from or to the bolt A on an antenna platform level. GPS13A 06216 11gp 0.938-1.57707 0.03-1.577036 06216 GPS8A 11gp 1.093-3.65628 0.04-3.656241 GPS8A GPS8 * 11gp 0.018 2.46893 0.01 2.468943 GPS8 * GPS8B 11gp 0.020-2.04577 0.01-2.045756 GPS8B 03217 11gp 0.796 6.10672 0.03 6.106749 03217 AP41 11gp 0.808-1.96948 0.03-1.969451 AP41 GPS4B 11gp 0.604-1.28085 0.26-1.280590 GPS4B GPS4C 11gp 0.011-0.10040 0.01-0.100392 GPS4C AP41 11gp 0.610 1.38072 0.26 1.380982 AP41 GPS1A 11gp 0.358 0.26575 0.01 0.265763 GPS1A GPS1B 11gp 0.016 0.30564 0.00 0.305641 GPS1B 03218 11gp 0.820-0.51221 0.03-0.512180 03218 AP6 11gp 1.258-0.74937 0.05-0.749325 AP6 GPS2B 11gp 0.233 3.30751-0.06 3.307453 GPS2B GPS2 * 11gp 0.030 2.37125-0.02 2.371227 GPS2 * GPS2A 11gp 0.026-2.41310-0.02-2.413120 GPS2A AP6 11gp 0.245-3.26550-0.06-3.265560 AP6 03216 11gp 0.531 1.63448 0.02 1.634499 03211 GPS17A GP17 1.246 14.60404 0.02 14.604065 GPS17A GPS17B GP17 0.014-0.51060 0.00-0.510603 GPS17B GPS17C GP17 0.012-0.26448 0.00-0.264483 GPS17C GPS17N GP17 0.011 1.31254 0.00 1.312538 GPS17N GPS17 * GP17 0.015 1.76367-0.02 1.763650 GPS17 * GPS17N GP17 0.015-1.76363-0.02-1.763650 GPS17N GPS17A GP17 0.009-0.53745 0.00-0.537452 GPS17A AP17 GP17 0.471-5.82371 0.01-5.823701 AP17 03211 GP17 0.778-8.78038 0.02-8.780364 GPS18A GPS18B GP18 0.013-0.26289 0.01-0.262879 GPS18B GPS18C GP18 0.010 0.32153 0.01 0.321539 GPS18C GPS18N GP18 0.006 0.91039 0.01 0.910395 GPS18N GPS18 * GP18 0.015 1.76361-0.01 1.763600 GPS18 * GPS18N GP18 0.015-1.76359-0.01-1.763600 GPS18N GPS18A GP18 0.006-0.96906 0.01-0.969055 GPS18A AP18 GP18 1.254-7.82693 0.00-7.826930 AP18 GPS16C GP18 1.125 3.89836 0.00 3.898360 GPS16C GPS16A GP18 0.009-0.15578-0.01-0.155792 GPS16A GPS16B GP18 0.010 0.46437-0.01 0.464357 GPS16B GPS16N GP18 0.006 0.26948-0.01 0.269472 GPS16N GPS16 * GP18 0.018 1.75670 0.00 1.756700

11 GPS16 * GPS16N GP18 0.018-1.75670 0.00-1.756700 GPS16N GPS16C GP18 0.005-0.57803-0.01-0.578037 GPS16C AP5 GP18 0.099-2.60347 0.00-2.603470 04005 AP20 GP19 0.458 5.64525-0.13 5.645123 AP20 AP19 GP19 1.020-2.75143 0.03-2.751400 AP19 GPS19A GP19 0.483 4.64896 0.03 4.648990 GPS19A GPS19B GP19 0.011 0.42316-0.01 0.423149 GPS19B GPS19C GP19 0.013-0.43253-0.01-0.432543 GPS19C GPS19N GP19 0.007 0.97958-0.01 0.979573 GPS19N GPS19 * GP19 0.017 1.76515 0.03 1.765180 GPS19 * GPS19N GP19 0.017-1.76521 0.03-1.765180 GPS19N GPS19A GP19 0.008-0.97017-0.01-0.970178 GPS19A AP19 GP19 0.485-4.64902 0.03-4.648990 AP19 AP20 GP19 1.023 2.75137 0.03 2.751400 AP20 04005 GP19 0.458-5.64524 0.12-5.645123 10301 GPS6A GP6A 1.267-7.39698 0.05-7.396934 GPS6A GPS6B GP6A 0.010-0.19859 0.00-0.198587 GPS6B GPS7A GP6A 0.858 7.49665 0.03 7.496681 GPS7A GPS7B GP6A 0.012 0.07765 0.00 0.077649 GPS7B GPS13B GP6A 1.411-1.88435 0.05-1.884299 GPS13B GPS13A GP6A 0.012 0.32369 0.00 0.323688 GPS13A GPS13 * GP6A 0.028 1.29040 0.00 1.290395 GPS13 * GPS13B GP6A 0.021-1.61408 0.00-1.614084 GPS6A GPS6 * GP6S 0.033 2.30445-0.01 2.304441 GPS6 * GPS6B GP6S 0.032-2.50302-0.01-2.503028 GPS9B GPS9 * GP9S 0.045 3.11365-0.01 3.113641 GPS9 * GPS9A GP9S 0.027-2.58911-0.01-2.589115 GPS2A GPS2B GPS2 0.014 0.04190-0.01 0.041893 GPS4C GPS4 * GPS4 0.025 2.62121 0.01 2.621217 GPS4 * GPS4B GPS4 0.022-2.52083 0.01-2.520824 GPS7A GPS7 * GPS7 0.029 2.34993 0.00 2.349934 GPS7 * GPS7B GPS7 0.027-2.27229 0.00-2.272286 GPS8A GPS8B GPS8 0.005 0.42319 0.00 0.423187 51310 03212 LAPI 0.078 1.48152 0.00 1.481520 03212 03202 LAPI 0.828-3.26841 0.00-3.268410 03202 03203 LAPI 2.077-6.05593 0.00-6.055930 03203 03204 LAPI 1.852-0.36882 0.00-0.368820 03204 04001 LAPI 0.017 1.12264 0.00 1.122640 04001 04002 LAPI 2.065 13.28382 0.00 13.283820 04002 03205 LAPI 0.014 0.45371 0.00 0.453710 03205 04003 LAPI 1.508-14.92267 0.00-14.922670 04003 03206 LAPI 0.019 0.41784 0.00 0.417840 03206 AP4 LAPI 1.007-8.52689 0.00-8.526890

12 AP4 03207 LAPI 1.009 1.22646 0.00 1.226460 03207 AP20 LAPI 0.452 4.91772 0.00 4.917720 AP20 04005 LAPI 0.458-5.64488-0.24-5.645123 04005 03211 LAPI 0.037-0.90850 0.00-0.908500 03211 08204 LAPI 0.208 0.63439-0.08 0.634315 08204 08203 LAPI 0.392 3.91000-0.11 3.909890 08203 03208 LAPI 0.126 3.62796-0.01 3.627950 03208 04004 LAPI 0.051 0.27933-0.07 0.279261 04004 AP5 LAPI 0.739-6.68498 0.00-6.684980 AP5 03216 LAPI 1.564 6.21473 0.00 6.214730 03216 03219 LAPI 0.018 1.02025-0.05 1.020201 GPS3B GPS3 * OLKB 0.034 2.47578 0.04 2.475822 GPS3 * GPS3A OLKB 0.029-2.55055 0.04-2.550514 GPS3A GPS3B OLKB 0.011 0.07468 0.01 0.074692 GPS3B 03218 OLKB 0.851 2.73202-0.11 2.731915 03218 GPS3A OLKB 0.862-2.80650-0.11-2.806607 03216 06220 on11 0.616 0.45292-0.05 0.452867 06220 08201 on11 0.075 0.72774 0.08 0.727820 08201 06221 on11 0.036 4.03750-0.02 4.037480 06221 08201 on11 0.036-4.03746-0.02-4.037480 08201 06220 on11 0.075-0.72790 0.08-0.727820 06220 08202 on11 0.050-0.42802 0.00-0.428024 08202 06219 on11 0.081 0.02405-0.01 0.024043 06219 06218 on11 0.377 0.42024-0.03 0.420207 06218 06217 on11 0.331-2.44468-0.03-2.444709 06217 10301 on11 0.193 3.28583-0.02 3.285813 10301 03219 on11 0.789-0.28990-0.10-0.289997 03219 03216 on11 0.018-1.02015-0.05-1.020201 04005 03211 st11 0.037-0.90850 0.00-0.908500 03211 08204 st11 0.208 0.63424 0.07 0.634315 08204 08203 st11 0.392 3.90978 0.11 3.909890 08203 03208 st11 0.126 3.62794 0.01 3.627950 03208 04004 st11 0.052 0.27919 0.07 0.279261 GPS9A GPS9B vl11 0.014-0.52452-0.01-0.524526 GPS9B 06213 vl11 0.074 1.36777-0.02 1.367754 06213 06214 vl11 0.126-0.61934-0.03-0.619367 06214 06215 vl11 0.078 1.08338 0.04 1.083415 06215 06216 vl11 0.114-3.40046 0.05-3.400409 06216 06214 vl11 0.141 2.31693 0.06 2.316994 06214 GPS9A vl11 0.103-0.22384-0.02-0.223862

13 Table 6. Benchmarks in the 2011 adjustment and their KKJ coordinates in zone 27 and geographical coordinates longitude ( ) and latitude ( ), height (m), precision (mm). * = Measured to the bolt A on an antenna platform level. Adjusted height includes the height of the bolt A 19.912 mm. AP4 6801288.0 3207835.0 21.556712 61.210691 1.950816 0.47 AP5 6803292.0 3205355.0 21.507655 61.226734 3.307808 0.28 AP6 6804240.0 3204526.0 21.490810 61.234577 7.888039 0.16 AP17 6801972.0 3205913.0 21.520051 61.215362 10.321737 0.41 AP18 6803940.0 3206075.0 21.519986 61.233064 2.012918 0.38 AP19 6803133.0 3206564.0 21.530305 61.226222 5.343596 0.42 AP20 6802183.0 3206796.0 21.536079 61.217909 8.094996 0.38 AP41 6804956.0 3203363.0 21.468130 61.240092 8.578141 0.33 GPS2 * 6804131.0 3204730.0 21.494761 61.233757 13.566719 0.18 GPS3 * 6805666.0 3204240.0 21.483271 61.247098 8.381271 0.32 GPS4 * 6805522.0 3203497.0 21.469723 61.245249 9.818375 0.36 GPS6 * 6804680.0 3202353.0 21.449845 61.236859 5.740243 0.28 GPS7 * 6805344.0 3202190.0 21.445775 61.242666 13.08383 0.32 GPS8 * 6805838.0 3202321.0 21.447423 61.247178 6.486599 0.37 GPS9 * 6805467.0 3201329.0 21.429621 61.243108 12.356144 0.38 03202 6796404.0 3213568.0 21.670307 61.171287 16.547116 0.82 03203 6797157.0 3212085.0 21.641726 61.176929 10.491186 0.75 03204 6798578.0 3211060.0 21.620590 61.188871 10.122366 0.68 03205 6799810.0 3209568.0 21.591082 61.198775 24.982536 0.60 03206 6800808.0 3208659.0 21.572714 61.207016 10.477706 0.52 03207 6802055.0 3207228.0 21.544281 61.217089 3.177276 0.41 03208 6802779.0 3205831.0 21.517275 61.222509 9.713527 0.35 03211 6802314.0 3206363.0 21.527854 61.218755 1.541372 0.37 03212 6796290.0 3214189.0 21.681969 61.170722 19.815526 0.84 03216 6804168.0 3204117.0 21.483343 61.233624 9.522538 Fixed 03217 6805553.0 3202853.0 21.457735 61.245037 10.547591 0.36 03218 6805010.0 3203976.0 21.479407 61.241039 8.637364 0.28 03219 6804154.0 3204109.0 21.483216 61.233493 10.542739 0.02 04001 6798581.0 3211035.0 21.620123 61.188880 11.245006 0.68 04002 6799826.0 3209568.0 21.591058 61.198918 24.528826 0.60 04003 6800788.0 3208647.0 21.572522 61.206829 10.059866 0.53 04004 6802736.0 3205815.0 21.517045 61.222113 9.992788 0.35 04005 6802334.0 3206392.0 21.528361 61.218955 2.449872 0.37 06213 6805403.0 3201332.0 21.429778 61.242539 10.610257 0.38 06214 6805445.0 3201428.0 21.431491 61.242987 9.99089 0.38 06215 6805398.0 3201444.0 21.431862 61.242580 11.074305 0.38 06216 6805469.0 3201501.0 21.432806 61.243257 7.673897 0.37 06217 6804590.0 3203605.0 21.473191 61.237006 7.546922 0.17

14 06218 6804655.0 3203890.0 21.478371 61.237803 9.991631 0.18 06219 6804478.0 3204044.0 21.481503 61.236338 9.571423 0.16 06220 6804432.0 3203953.0 21.479889 61.235858 9.975405 0.15 06221 6804349.0 3203994.0 21.480779 61.235148 14.740705 0.16 08201 6804380.0 3203998.0 21.480805 61.235428 10.703225 0.16 08202 6804442.0 3203990.0 21.480559 61.235976 9.54738 0.16 08203 6802685.0 3205930.0 21.519255 61.221744 6.085577 0.35 08204 6802470.0 3206180.0 21.524222 61.220011 2.175687 0.37 10301 6804536.0 3203479.0 21.470941 61.236428 10.832736 0.16 51310 6796265.0 3214232.0 21.682802 61.170530 18.334006 0.84 GPS13 * 6804815.0 3201194.0 21.428152 61.237182 10.541328 0.36 GPS16 * 6803298.0 3205453.0 21.509461 61.226861 8.246015 0.29 GPS17 * 6801908.0 3205596.0 21.514279 61.214552 18.446539 0.41 GPS18 * 6804712.0 3205623.0 21.510404 61.239620 12.572503 0.46 GPS19 * 6803466.0 3206526.0 21.529082 61.229168 12.727944 0.43 GPS1A 6804893.0 3203610.0 21.472807 61.239717 8.843903 0.32 GPS1B 6804877.0 3203609.0 21.472814 61.239573 9.149544 0.32 GPS2A 6804123.0 3204733.0 21.494829 61.233688 11.153599 0.18 GPS2B 6804132.0 3204723.0 21.494630 61.233761 11.195492 0.18 GPS3A 6805668.0 3204247.0 21.483398 61.247121 5.830757 0.32 GPS3B 6805674.0 3204238.0 21.483222 61.247168 5.905449 0.32 GPS4B 6805534.0 3203495.0 21.469667 61.245355 7.29755 0.36 GPS4C 6805522.0 3203517.0 21.470094 61.245264 7.197158 0.36 GPS6A 6804687.0 3202356.0 21.449890 61.236924 3.435801 0.28 GPS6B 6804683.0 3202348.0 21.449748 61.236882 3.237214 0.28 GPS7A 6805336.0 3202192.0 21.445825 61.242596 10.733895 0.32 GPS7B 6805342.0 3202181.0 21.445611 61.242641 10.811544 0.32 GPS8A 6805842.0 3202324.0 21.447472 61.247216 4.017656 0.37 GPS8B 6805837.0 3202326.0 21.447517 61.247173 4.440843 0.37 GPS9A 6805475.0 3201335.0 21.429719 61.243184 9.767028 0.38 GPS9B 6805472.0 3201321.0 21.429465 61.243147 9.242503 0.38 GPS13A 6804810.0 3201186.0 21.428012 61.237131 9.250933 0.36 GPS13B 6804806.0 3201197.0 21.428222 61.237104 8.927245 0.36 GPS16A 6803301.0 3205457.0 21.509531 61.226891 5.755486 0.29 GPS16B 6803293.0 3205456.0 21.509525 61.226819 6.219843 0.29 GPS16C 6803302.0 3205448.0 21.509363 61.226893 5.911278 0.29 GPS16N 6803297.0 3205453.0 21.509463 61.226852 6.489315 0.29 GPS17A 6801902.0 3205601.0 21.514381 61.214502 16.145437 0.41 GPS17B 6801909.0 3205590.0 21.514167 61.214556 15.634834 0.41 GPS17C 6801918.0 3205598.0 21.514301 61.214643 15.370352 0.41 GPS17N 6801909.0 3205596.0 21.514278 61.214561 16.682889 0.41 GPS18A 6804714.0 3205629.0 21.510512 61.239642 9.839848 0.46 GPS18B 6804705.0 3205620.0 21.510359 61.239555 9.576969 0.46

15 GPS18C 6804715.0 3205619.0 21.510325 61.239644 9.898508 0.46 GPS18N 6804713.0 3205623.0 21.510402 61.239629 10.808903 0.46 GPS19A 6803475.0 3206527.0 21.529087 61.229249 9.992586 0.43 GPS19B 6803466.0 3206533.0 21.529212 61.229173 10.415734 0.43 GPS19C 6803462.0 3206520.0 21.528977 61.229128 9.983191 0.43 GPS19N 6803467.0 3206526.0 21.529081 61.229177 10.962764 0.43

16

17 4 COMPARISON WITH PREVIOUS LEVELLINGS The heights and height differences for 2010 and 2011 are from Tables 3-6. The results of Lehmuskoski (2008 and 2010) were adopted for the previous levellings. Land uplift corrections were not used for computing the results for the loops on the Olkiluoto island or the line Olkiluoto strait where the theoretical changes of land uplift are very small. The N60 elevation derived in 03216 from the campaign in 2003 was fixed for the later campaigns. When the N60 elevations of GPS points were compared, we used the mean of their reserve mark pair with the exceptions of GPS2 and GPS4, whose other pair had been damaged. 4.1 Standard deviations for the comparisons between levelling The accuracies of the levelling in 2010 and 2011 from the adjustments are τ = ± 0.27 mm/ km in 2010 and τ = ± 0.23 mm/ km in 2011. This accuracy includes small GPS loops. Without these small loops accuracy would be τ = ± 0.25 mm/ km. For the previous levelling accuracies were estimated in Lehmuskoski (2010) by the Formula 1. (Kääriäinen 1966). 2 n 2 2 1 i e, (1) n 1 i 1 Fi Fe where n = number of the loops, φ i = closing error of the loop, F i = circumference of the loop, φ e = closing error of the circumference of the network and F e = length of the circumference of the network. Accuracy estimates for all levelling campaigns are given in Table 7. Table 7. Accuracy estimates for levelling campaigns ( / ). 2003 2005 2006 2007 2008 2009 2010 2011 ±0.10 ±0.14 ±0.17 ±0.23 ±0.12 ±0.14 ±0.27 ±0.23 When we compare the results of two campaigns, the standard deviation of their difference is estimated by the formula τ Δ 2 = τ 1 2 + τ 2 2, where τ 1 and τ 2 are the accuracies of the comparable campaigns. The standard deviations for the comparisons are presented in Table 8. Table 8. Standard deviations τ Δ 2 for the comparisons. 2011-2010 0.35 mm/ km 2011-2009 0.27 mm/ km 2010-2009 0.30 mm/ km 2011-2008 0.26 mm/ km 2010-2008 0.30 mm/ km 2011-2007 0.33 mm/ km 2010-2007 0.35 mm/ km 2011-2006 0.29 mm/ km 2010-2006 0.32 mm/ km 2011-2005 0.27 mm/ km 2010-2005 0.30 mm/ km 2011-2003 0.25 mm/ km 2010-2003 0.29 mm/ km

18 The critical value can be considered significant, when the change of the elevation is more than threefold of the standard deviation of the discrepancy: T D 3 For instance, if the elevation difference of one kilometre long interval has changed from 2005 to 2010 more than 0.90 mm, the change can be considered to be significant. 4.2 Lapijoki-Olkiluoto Levelling line Lapijoki-Olkiluoto has been measured every fourth year. This 14 kilometres long line connects the GPS network on the Olkiluoto island to the precise levelling network of Finland at Lapijoki. Levelling results measured in 2003 and 2011 indicate that Olkiluoto island is not uplifting or going down relative to Lapijoki. Land uplift corrected height difference from 2003 to 2011 is -1.09 mm (Fig. 2). Without land uplift correction difference is only 0.27 mm. From NKG2005 land uplift model (Ågren and Svensson, 2007) we get that during one year land uplift at Olkiluoto is 0.17 mm more than at Lapijoki (Table 9). Benchmark interval 03206-03207 has a significant difference in comparison with 2007 levelling (Table 9). In Olkiluoto strait 04005-03211 has significant deformation (Table 10). When we compare the latest levelling to 2003 the situation is different. There seem to be eight benchmark intervals which have changed significantly since 2003. It is interesting to see that Olkiluoto strait interval 03208-03211 has changed only 0.44 mm since 2007 (Fig. 3). 2,00 1,38 1,20 1,00 0,00 0,30 0,14 0,05 0,52 1,36 0,40 0,04 1,14 1,09 0,00 51310 03212 03202 03203 03204 03205 03206 03207 03211 03208 03216 03219 1,00 0,00 0,09 0,55 0,22 0,28 0,69 0,51 2,00 3,00 4,00 5,00 2,07 2,28 2,75 3,77 3,70 Land uplift corrected 2011 2007 Land uplift corrected 2011 2003 Figure 2. Line Lapijoki-Olkiluoto. Land uplift corrected height differences in Lapijoki- Olkiluoto line between previous levellings in 2003 and 2007 and the new levelling in 2011 (in millimetres).

19 Table 9. Significance of the elevation differences in Lapijoki-Olkiluoto line. Change of the elevation difference (mm). Corrected for land uplift. Significance of the standard deviation Distance (km) NKG2005 land uplift (mm/y) 2011-2007 2011-2003 2011-2007 2011-2003 2007-2003 Lehmuskoski(2008) 51310 0.00 5.26946 0.000 0.000 0.0 0.0 0.0 03212 0.08 5.27010-0.093 0.304 0.0 4.4 5.6 03202 0.83 5.27598-0.453-0.706 1.5 2.9 1.1 03203 2.06 5.29643 0.328 0.266 0.7 1.2 0.2 03204 1.85 5.32235-0.064 1.517 0.1 5.1 4.6 03205 2.08 5.34866-0.405-1.335 0.9 3.1 2.6 03206 1.52 5.36765 0.174 1.158 0.4 4.2 3.2 03207 2.02 5.39296-1.561-1.727 3.3 4.3 0.5 03211 0.93 5.40183-0.209-0.839 0.7 3.2 2.6 03208 0.75 5.41107-0.472 1.406 1.7 6.8 8.7 03216 2.37 5.43911-1.011-1.188 2.0 2.5 0.5 03219 0.02 5.43899 0.061 0.061 1.3 1.8 0.0 4.3 Olkiluoto strait The 2007 observations indicated that between 2003 and 2007 the benchmark 03208 on the Olkiluoto island had lifted 1.91 mm up compared to the benchmark 03211 on the continent. This was the motivation to start yearly measurements over the Olkiluoto strait. The elevation change of this interval has returned since 2007 (Fig. 3). At the moment the most interesting deformation happens in a short, only 39 metres long, the interval between benchmarks 03211 and 04005. It has been measured twice in 2011 and both measurements gave same height difference of 908.50 mm. This value is about a half millimetre more than in the previous measurements and is significant (Fig. 4, Fig. 5 and Table 10).

20 2,50 Change of elevation difference in 03211 03208 2,00 1,50 1,91 1,48 1,58 1,47 1,00 1,09 0,50 0,00 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Figure 3. Elevation change of interval 03211-03208 relative to 2003 observation. Figure 4. Line Olkiluoto strait has six benchmarks. At the moment most active part of the line is 04005-03211.

21 0,70 0,60 0,50 0,40 0,30 0,20 2010 2009 2011 2009 0,10 0,00 03211 04005 08204 08203 03208 04004 0,10 0,20 Figure 5. Elevation differences in the line Olkiluoto strait between previous levelling in 2009 and the new levellings in 2010 and 2011 (in millimetres). Table 10. Elevation differences in the Olkiluoto strait in 2004-2011 and significance of an elevation difference between the latest measurements. The elevation differences (mm). Not corrected for land uplift. 2004 2007 2008 2009 2010 2011 03211 0 0 0 Distance mean(km) Significance of height change 2010-09 2011-09 04005 907.99 908.06 908.05 908.10 908.00 908.50 0.039 1.7 7.5 7.3 08204-273.88-273.99-273.83-274.19 0.226 1.1 1.6 2.2 08203 3909.97 3909.65 3910.12 3909.89 0.402 2.5 1.4 1 03208 3628.02 3628.01 3627.97 3627.95 0.128 0.4 0.6 0.2 04004 279.88 279.04 279.16 279.08 279.20 279.26 0.051 1.8 2.9 0.8 2011-10 According to Lehmuskoski (2010) the 2004 measurement of interval 03208-04004 was levelled 31 st of March and other measurements have been done in late autumn and the reason for the elevation difference is thus the different temperature of bedrock in March and September, estimated to be about 15 C in the vicinity of the surface of the bedrock (Lehmuskoski et al. 2006). 4.4 OLKIA and OLKIB The loop OLKIA has been measured in 2003, 2005, 2007, 2009 (Lehmuskoski 2004, 2006, 2008 and 2010) and 2011. Like in earlier levelling reports the elevation differences were computed in millimetres and land uplift correction was not applied. In order to compare the N60 elevations to earlier campaigns the height of the nodal

22 benchmark 03216 derived in 2003 (9522.538 mm) was kept fixed. In Fig. 8 deformation history of ONKALO can be seen. According to Lehmuskoski (2010) the most remarkable deformation in loop OLKIA has been at GPS6 in 2003-2009 and at GPS13 in 2007-2009. The reason for the changes were large construction works near these stations, parking area around GPS6 and nuclear power station of Olkiluoto 3 near GPS13. Lehmuskoski (2010) has analyzed that the northern part of the Olkiluoto island rises compared to the middle and southern parts (Fig. 6). Using 2011 observations we can see that the movement of GPS6 is minimal relative previous measured in 2009. The most significant movement has been from GPS7 to GPS13 (Fig. 9 and Table 11). When we compare uplift 2009-2011 relative to 03216 we can see that only GPS6 and GPS7 are stable. GPS13 has uplifted 0.8 mm and other benchmarks 0.35-0.65 mm (Fig. 9). Loop OLKIB connects GPS3 to 03218. This interval has been stable during the years, and no significant deformation has happened since previous measurements (Table 12 and Fig. 7). Figure 6. Deformation in Loop OLKIA 2003-2009. Change of N60 elevation compared to benchmark 03216 in 2003. Red bar gives the change to 2005, blue bar to 2007 and black bar to 2009 (Lehmuskoski 2010).

23 Figure 7. Loops OLKI A and OLKI B. 1,80 1,60 1,40 1,20 1,00 0,80 0,60 0,40 2009 >2011 2007 >2011 2005 >2011 2003 >2011 0,20 0,00 0,20 03216 GPS6 GPS7 GPS9 GPS8 03217 GPS4 GPS1 03218 GPS2 03216 Figure 8. Deformation in Loop OLKIA relative to benchmark 03216. Since 2003 has GPS6 raised 1.6 mm, GPS9 1.3 mm and GPS4 almost 1.6 mm. In this picture GPS station deformation is focused on the mean movement of the reserve marks.

24 2011 2009 1,00 0,82 0,82 0,80 0,65 0,64 0,60 0,50 0,40 0,52 0,41 0,41 0,20 0,06 0,00 0,08 0,04 0,35 0,11 0,00 0,20 0,44 0,40 0,40 0,41 0,00 Figure 9. Height differences in Loop OLKIA between previous levelling in 2009 and the new levelling in 2011 (in millimetres).

Table 11. Significance of elevation difference changes between 2011 and previous levellings in loop OLKIA. N60 2011 Observation 2011 Distance km 2011-03 Elev. difference and significance 2011-05 Elev. difference and significance 2011-07 Elev. difference and significance 2011-09 Elev. difference and significance 03216 9522.538 0 0 0 0 0 GPS6A 3435.801-6086.737 2.080 1.552 4.3 0.601 1.7 0.616 1.3-0.056 0.1 GPS6B 3237.214-198.587 0.010 0.093 3.7-0.007 0.3 0.004 0.1-0.027 1.0 GPS7A 10733.895 7496.681 0.860-0.988 4.3-0.137 0.6-0.146 0.5 0.047 0.2 GPS7B 10811.544 77.649 0.012-0.071 2.6 0.049 1.8 0.147 4.1-0.071 2.4 GPS13B 8927.245-1884.299 1.411 - - -0.137 0.5-0.324 0.8 0.924 2.9 GPS13A 9250.933 323.688 0.012 - - -0.14 5.1-0.122 3.4-0.002 0.1 GPS9A 9767.028 516.095 1.180 0.759 1.9 0.135 0.5 0.317 0.9-0.299 1.0 GPS9B 9242.503-524.525 0.010-0.115 4.6-0.066 2.6 0.013 0.4-0.016 0.6 GPS8A 4017.656-5224.847 1.540-0.46 1.5 0.118 0.4-0.451 1.1-0.093 0.3 GPS8B 4440.843 423.187 0.380 0.017 0.1 0.037 0.2 0.037 0.2 0.007 0.0 03217 10547.591 6106.748 0.796 0.392 1.8 0.612 2.7 0.161 0.5 0.234 1.0 GPS4B 7297.550-3250.041 1.404 0.364 1.2 0.269 0.9 0.414 1.1-0.007 0.0 GPS1A 8843.903 1546.353 0.980-0.692 2.8-0.618 2.5-0.523 1.6-0.292 1.1 GPS1B 9149.544 305.641 0.016-0.019 0.6 0.121 3.8 0.089 2.1 0.091 2.7 03218 8637.364-512.180 0.820-0.137 0.6 0.093 0.4 0.134 0.4-0.044 0.2 GPS2B 11195.492 2558.128 1.490-0.456 1.5-0.713 2.3-0.143 0.4 0.002 0.0 GPS2A 11153.599-41.893 0.056 0.257 4.3 0.267 4.5 0.299 3.8 0.007 0.1 03216 9522.538-1631.061 0.790-0.496 2.2-0.484 2.2-0.522 1.8-0.405 1.7 25

26 Table 12. Observations in loop OLKIB in 2011 and comparison with the previous measurements. In this loop there is no any significant change between measurements. N60 2011 Obs 2011 Distance 03218 8637.364 0.000 2011-03 Elev. difference and significance 2011-05 Elev. difference and significance 2011-07 Elev. difference and significance 2011-09 Elev. difference and significance GPS3B 5905.449-2731.915 0.851 0.365 1.6 0.225 1.0 0.025 0.1-0.075 0.3 GPS3A 5830.757-74.692 0.011 0.030 1.1 0.050 1.9 0.050 1.4 0.010 0.4 03218 8637.364 2806.607 0.862-0.395 1.7-0.275 1.2-0.075 0.2 0.065 0.3 4.5 Micro loop ONKALO According to Lehmuskoski (2010) the most interesting benchmark in ONKALO is 06220 (Fig. 10 and Fig. 11). Other benchmarks show rather small vertical movements. Benchmark 06220 over ONKALO compared to the nodal benchmark 03216 was lifted almost one millimetre between the levelling in 2007-2008. In 2009 it was almost on the same level as in 2008 but the direction of the movement was still upwards. In Lehmuskoski (2010) other interesting question was if benchmark 08201 could belong to the same rising area. New observations in 2010 and 2011 give negative answer to that question. Both benchmarks 06220 and 08201 were at a lower level relative to 03216 in 2010 and 2011 than in 2009. Figure 10. Loop ONKALO.

27 The new measurements did not indicate any active crustal deformation over ONKALO. All the elevation differences between 2009, 2010 and 2011 were below statistically significant level. Comparison between previous levelling in 2009 and the new levelling in 2010 are in Table 13 and for 2011 in Table 14. Figure 11. Change of N60 elevation compared to benchmark 03216 in 2006 in Loop ONKALO. Red bar gives the change to 2007, blue bar to 2008 and black bar to 2009. Black numbers (-0.1) give the change of N60 elevation 2009-2008 (Fig. 6., Lehmuskoski 2010). 0,10 0,00 0,02 0,08 0,08 0,02 0,06 0,10 0,16 0,00 0,00 03216 06217 06218 06219 08202 06220 06221 08201 03216 0,10 0,20 0,25 0,26 2010 2009 2011 2009 0,30 0,37 0,40 0,50 0,39 0,39 0,44 0,44 Figure 11. Differences in N60 heights relative to 03216 in Loop ONKALO.

28 Table 13. Elevation difference and significance of the difference between 2010 observations and previous measurements in Loop ONKALO. N60 2010 03216 9522.538 Obs. 2010 Distance 2010, km Elevation difference and significance in 2010-06 Elevation difference and significance in 2010-07 Elevation difference and significance in 2010-08 Elevation difference and significance in 2010-09 06217 7546.506-1976.032 1.010-0.736 2.3-0.506 1.4-0.378 1.3-0.396 1.3 06218 9991.317 2444.811 0.334 0.307 1.7-0.033 0.2 0.019 0.1 0.007 0.0 06219 9571.247-420.070 0.390 0.310 1.6 0.310 1.4-0.005 0.0 0.140 0.7 08202 9547.138-24.109 0.082 0.028 0.3-0.008 0.1 06220 9975.027 427.889 0.050 0.692 9.7 0.112 1.4-0.023 0.3-0.190 2.8 06221 14740.433 4765.406 0.103-0.741 6.4-0.251 2.0-0.209 2.2 0.069 0.7 08201 10702.951-4037.482 0.034 0.049 0.9-0.062 1.1 03216 9522.538-1180.413 0.753 0.168 0.6 0.368 1.2 0.519 2.0 0.440 1.7

Table 14. Elevation difference and significance of the difference between 2011 observations and previous measurements in Loop ONKALO. N60 2011 Obs. 2011 Distance 2011.km Elevation difference and significance in 2011-06 Elevation difference and significance in 2011-07 Elevation difference and significance in 2011-08 Elevation difference and significance in 2011-09 Elevation difference and significance in 2011-10 03216 9522.538 0.000 0.000 0.0 0.000 0.0 0.000 0.0 0.000 0.0 0.000 0.0 06217 7546.922-1975.616 1.000-0.320 1.1-0.090 0.3 0.038 0.1 0.020 0.1 0.416 1.2 06218 9991.631 2444.709 0.331 0.205 1.2-0.135 0.7-0.083 0.6-0.095 0.6-0.102 0.5 06219 9571.423-420.208 0.337 0.172 1.0 0.172 0.9-0.143 0.9 0.002 0.0-0.138 0.7 08202 9547.38-24.043 0.081 0.094 1.3 0.058 0.8 0.066 0.7 06220 9975.405 428.025 0.050 0.894 8.5 0.314 2.6 0.113 1.9-0.054 0.9 0.136 1.7 06221 14740.71 4765.300 0.111-0.847 8.8-0.357 3.2-0.315 3.6-0.037 0.4-0.106 0.9 08201 10703.23-4037.480 0.036 0.051 1.0-0.060 1.2 0.002 0.0 03216 9522.538-1180.687 0.691-0.104 0.4 0.096 0.3 0.245 1.1 0.166 0.7-0.274 0.9 29

30 4.6 Micro Loop VLJ According to Lehmuskoski (2010) there are some movements in loop VLJ (Fig. 13), which exceed a significance limit but are not systematic, and can be related to the temperature differences of the bedrock during different years. Another remark in Lehmuskoski (2010) is about the intervals 06213-06214 and 06215-06216 where the elevation difference increase systematically but does not yet exceed the significance limit (Fig. 12 and Table 15). The difference between 2010 and 2011 measurements in interval GPS9A-06213 is 0.67 mm. It is a significant deformation in this 88 metres long interval (Fig. 14 and Table 17). Deformation in the intervals 06213-06214 and 06215-06216 were well below significant level. Figure 12. Deformation analysis picture based on levellings 2006-2009 (Lehmuskoski 2010, Fig. 7). Change of N60 elevation compared to reserve mark GPS9B in 2006 in Loop VLJ. Red bar gives the change to 2007, blue bar to 2008 and green bar to 2009 ).

31 Table 15. Significance of N60 elevation changes of intervals (Lehmuskoski 2010, Table 16). Interval Distance Change of N60 elevation Significance of standard (km) (mm) deviation 2006 2007 2006 2008 2006 2009 2006 2007 2006 2008 2006 2009 GPS9A GPS9B 0.02-0.11 0.03-0.07 2.6 1.4 3.2 GPS9B 06213 0.09 0.36 0.28 0.03 4.0 4.4 0.5 06213 06214 0.13 0.15 0.16 0.23 1.4 2.1 2.9 06214 06215 0.08-0.11-0.19-0.04 1.3 3.2 0.6 06215 06216 0.13 0.16 0.19 0.23 1.6 2.5 2.9 06216 GPS9A 0.32-0.45-0.46-0.37 2.9 3.9 3.0 Figure 13. Loop VLJ.

32 0,30 0,20 0,10 0,00 0,10 GPS9B GPS9A 06213 06214 06215 06216 GPS9B 2010 2009 2011 2009 0,20 0,30 0,40 Figure 14. Differences in N60 heights in Loop VLJ between previous levelling and the new levellings in 2010 and 2011 (in millimetres).

Table 16. Elevation difference and significance of the difference between 2010 observations and previous measurements in Loop VLJ. N60 2010 Observation 2010 GPS9B 9242.639 0 Distance 2011 km 2010-2006 Elev. difference and significance 2010-2007 Elev. difference and significance 2010-2008 Elev. difference and significance 2010-2009 Elev. difference and significance GPS9A 9767.028 524.389 0.014 0.046 1.2 0.152 3.7 0.018 0.5 0.118 3.3 06213 10610.927 843.899 0.890 0.322 1.1 0.065 0.2 0.010 0.0 0.367 1.3 06214 9991.421-619.506 0.126 0.177 1.6 0.031 0.2 0.021 0.2 0.056 0.5 06215 11074.729 1083.308 0.077 0.136 1.5 0.027 0.3 0.054 0.6 0.095 1.1 06216 7674.412-3400.32 0.122 0.267 2.4 0.109 0.9 0.081 0.8 0.041 0.4 GPS9B 9242.639 1568.227 0.256 0.584 3.6 0.026 0.1 0.148 1.0 0.139 0.9 Table 17. Elevation difference and significance of the difference between 2011 observations and previous measurements in Loop VLJ. N60 2011 Observation 2011 GPS9B 9242.503 0 Distance 2011 km 2011-2006 Elev. difference and significance 2011-2007 Elev. difference and significance 2011-2008 Elev. difference and significance 2011-2009 Elev. difference and significance 2011-2010 Elev. difference and significance GPS9A 9767.028 524.525 0.014 0.090 2.6 0.016 0.4 0.118 3.8 0.018 0.6 0.136 3.3 06213 10610.257 843.229 0.088 0.348 4.0 0.605 6.2 0.660 8.6 0.303 3.8 0.670 6.5 06214 9990.89-619.367 0.126 0.316 3.1 0.170 1.5 0.160 1.7 0.083 0.9 0.139 1.1 06215 11074.305 1083.415 0.078 0.029 0.4 0.080 0.9 0.161 2.2 0.012 0.2 0.107 1.1 06216 7673.897-3400.41 0.114 0.176 1.8 0.018 0.2 0.010 0.1 0.05 0.5 0.091 0.8 GPS9B 9242.503 1568.606 0.258 0.205 1.4 0.353 2.1 0.231 1.7 0.24 1.7 0.379 2.1 33

34 4.7 GPS antenna platform measurements Old GPS pillars in the Olkiluoto levelling network are GPS2, GPS3, GPS4, GPS6, GPS7, GPS8, GPS9 and GPS13. In 2011 measurements for the new GPS pillars GPS16, GPS17, GPS18 and GPS19 were performed. Old stations have two reserve marks. A new reserve mark GPS4C was established in 2011. New stations have four reserve marks: A, B, C and N. Measurements were performed so that the difference of the zero point of the rod scale from the bottom plate was eliminated during measurements. The levelling was focused on a bolt A on the antenna platform (Lehmuskoski 2006, Figures 5-6). To obtain the N60 elevation of the antenna platform, the height of the bolt, 19.912 mm have to reduce from the levelling results. The reserve mark GPS2B was measured in 2011. It was found to be damaged by a working machine in 2009 so it was not used in the comparison with the previous measurements. Explanation of the columns of Table 18: 1. Reserve mark 2. Corrected elevation difference from reserve mark to GPS antenna platform level ("A" bolt height 19,912 mm removed from the adjusted height difference) 3. From adjustment N60 elevation of the bolt on the antenna platform in 2011. 4. N60 elevation of the antenna platform in 2011 5. Mean height difference from the reserve marks to antenna platform 2011. In GPS2 only GPS2A was used and with GPS4 only GPS4B. 6. Mean height difference from the reserve marks to antenna platform 2009. In GPS2 only GPS2A was used and with GPS4 only GPS4B. 7. Change of the GPS antenna platform height difference from the reserve marks between 2011-2009 (mm). 8. Change in the GPS antenna platform N60 height relative to the benchmark 03216. N60 elevation difference 2011-2009 (mm).

35 Table 18. Height difference from reserve marks to GPS pillars in 2011. 1 2 3 4 5 6 7 8 GPS2A 2393.208 GPS2 GPS2 GPS2B 2351.315 13566.719 13546.807 2393.208 2393.226-0.018 0.384 GPS3A 2530.602 GPS3 GPS3 GPS3B 2455.910 8381.271 8361.359 2493.256 2493.261-0.005 0.325 GPS4B 2500.913 GPS4 GPS4 GPS4C 2601.305 9818.375 9798.463 2500.913 2500.951-0.038 0.603 GPS6A 2284.530 GPS6 GPS6 GPS6B 2483.117 5740.243 5720.331 2383.824 2383.848-0.024-0.094 GPS7A 2330.023 GPS7 GPS7 GPS7B 2252.374 13083.83 13063.918 2291.199 2291.116 0.083 0.011 GPS8A 2449.031 GPS8 GPS8 GPS8B 2025.844 6486.599 6466.687 2237.438 2237.406 0.032 0.442 GPS9A 2569.204 GPS9 GPS9 GPS9B 3093.729 12356.144 12336.232 2831.467 2831.436 0.031 0.539 GPS13A 1270.483 GPS13 GPS13 GPS13B 1594.171 10541.328 10521.416 1432.327 1432.321 0.006 0.822

36 Table 19. Observations from the reserve benchmarks to GPS antenna platform level for the GPS pillars established 2011 and the N60 heights of the GPS platform levels. At these values height of the bolt A 19.912 mm on the GPS platform level has been removed. Observation from reserve mark to GPS platform level (mm). N60 height of the GPS platform level in 2011 (mm). GPS16A 2470.617 (GPS16) 8226.103 GPS16B 2006.260 GPS16C 2314.825 GPS16N 1736.788 GPS17A 2281.19 (GPS17) 18426.627 GPS17B 2791.793 GPS17C 3056.275 GPS17N 1743.738 GPS18A 2712.743 (GPS18) 12552.590 GPS18B 2975.622 GPS18C 2654.083 GPS18N 1743.688 GPS19A 2715.446 (GPS19) 12708.030 GPS19B 2292.298 GPS19C 2724.841 GPS19N 1745.268

37 5 FUTURE PLANS The levelling in the loops and the lines will be continued according to the original plan: Autumn 2012: the micro loops ONKALO and VLJ and the line Olkiluoto strait. Autumn 2013: the micro loops ONKALO and VLJ and the loops OLKI A and OLKI B and the line Olkiluoto strait.

38

39 6 SUMMARY The precise levellings at Olkiluoto were started in autumn 2003. First measurements included GPS network and Lapijoki-Olkiluoto line which connects the Olkiluoto island to the precise levelling network of Finland. In 2006 micro networks over the underground facilities ONKALO and VLJ repository were established. Since 2007 the Olkiluoto strait line and loops over ONKALO and VLJ repository have been measured every year. In autumn 2007 the northern part of Olkiluoto island was found to rise compared to the middle and southern parts. The movements of GPS6 and GPS9 from 2003 to 2005 were significant. In 2007 this movement seemed to stop. In autumn 2009 GPS6 had uplifted again and GPS13 was found to sink. Between 2009-2011 GPS6 and GPS7 were stable but GPS13 was lifted 0.8 mm and other benchmarks in loop OLKIA were lifted 0.35-0.65 mm relative benchmark 03216. In 2007 the benchmark 06220 over ONKALO was discovered to rise unexpectedly. This movement continued in 2009 but in 2010 and 2011 the benchmark was at a lower level than in 2009. The ONKALO loop measurements done in 2009, 2010 and 2011 do not show any significants movements. In the VLJ loop the difference between 2010 and 2011 measurements in the benchmark interval GPS9A-06213 was 0.67 mm which is a significant height difference change when distance between the points is only 88 m. The Lapijoki-Olkiluoto line has been measured in 2003, 2007 and 2011. These measurements show that movement between Lapijoki and Olkiluoto island is small. There are some unstable intervals inside Lapijoki-Olkiluoto line. In comparison with 2003 observation in 2007 a remarkable movement was found in a benchmark interval 03208-03211 over the Olkiluoto strait. Later the movement over the Olkiluoto strait was found to be a little smaller and the measurement in 2011 gives the same result than 2007 measurement. The latest measurements show that the interval between benchmarks 04005 and 03211 had an elevation change between 2010 and 2011 measurements.