GPS velocity field in Arabia reference frame

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AR 49.64±0.58 5.06±2.27 0.579±0.019 Altamimi et al., (2007)

AR 50.209 4.162 0.567±0.011 SOPAC solution

AF 49.66±0.67 -83.81±1.58 0.251 ±0.004 This study

AF 49.95±0.48 -82.50±1.25 0.269±0.003 Altamimi et al., (2007)

AF 48.997 -80.424 0.275±0.003 SOPAC solution

AR-EU 27.53±0.6 17.71±0.8 0.393± 0.005 This study

AR-EU 27.5±0.1 17.6±0.3 0.404±0.004 ArRajehi et al., (2010)

AR-EU 28.4±0.9 18.4±1.0 0.428±0.009 Reilinger et al., (2006)

AR-EU 27.4±1.0 18.4±2.2 0.40±0.04 McClusky et al., (2003)

AR-EU 26.22±1.2 22.87±2.1 0.427±0.029 Sella et al., (2002)

AR-EU 27.9±0.5 19.5±1.4 0.41±0.1 Vernant et al., (2004)

AR-EU 24.6±2.3 13.7±5.0 0.5±0.05 NUVEL1-A (DeMets et al., 1994)

AR-AF 31.55±0.8 23.16±1.1 0.385±0.006 This study

AR-AF 31.7±0.2 24.6±0.3 0.369±0.005 ArRajehi et al., (2010)

AR-AF 31.5±0.6 25.2±0.7 0.393±0.005 Reilinger et al., (2006)

AR-AF 30.5±1.0 25.7±2.3 0.37±0.04 McClusky et al., (2003)

AR-AF 31.64±2.5 20.29±1.1 0.38±0.018 Vigny et al., (2006)

AR-AF 31.26±1.3 29.55±1.8 0.400±0.030 Sella et al., (2002)

AR-AF 31.5±1.2 23.0±2.7 0.40±0.05 Chu and Gordon (2002)

AR-AF 32.2 24 0.376 Joffe and Garfunkel (1987)

AR-AF 32.59 23.7 0.418 Jestin et al., (2007)

Table ‎III-6 : Euler vectors for Arabia (AR), Africa (AF), and Eurasia (EU) and the relative Euler poles of AR-EU and AR-AF this study and other previous studies. Our Euler poles are calculated from GPS vectors of this study. SOPAC solution (http://sopac.ucsd.edu/cgi- bin/poleRotationValues.cgi).

The Figure III.15 shows the velocity field in Eurasia reference frame for the campaign sites of our study in Syria and Turkey. The deformation and the relative plate movement cannot be visibly identified using this velocity field in such small region, therefore a velocity field in Arabian reference frame is needed in order to demonstrate the deformation along the plate boundaries and others faults which contribute to the kinematic of the junction.

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were minimized in the ITRF05 reference and an Euler pole of Arabian plate was calculated at 50.645±0.51 °N, -5.662±1.24 °E with an angular velocity of 0.507±0.014 °/Myr. The Arabia GPS Euler vector provides a very good fit to well constrained velocities at GPS sites distributed in the Arabia plate (Figure III.14) and it give a WRMS = 0.62 mm/yr.

Longitude Latitude

ITRF 2005 Arabia

Sig. E Sig. N Corr Site

Ve Vn Ve Vn

36.378 26.458 27.33 23.65 0.50 -0.34 0.67 0.78 -0.025 ALWJ

50.608 26.209 29.64 29.80 -0.34 0.09 0.52 0.52 0.001 BHR1

36.100 29.139 25.35 23.38 0.60 -0.49 0.46 0.53 -0.033 HALY

39.631 21.369 31.78 25.54 0.76 0.10 0.55 0.65 -0.041 JEDD

47.972 29.325 27.91 29.23 0.62 0.45 0.82 0.93 0.001 KUWT

42.045 19.211 33.29 26.79 0.47 0.32 0.56 0.58 -0.009 NAMA

46.401 24.911 30.44 28.61 0.54 0.42 0.52 0.52 -0.016 SOLA

56.112 22.186 33.58 30.96 0.00 -0.48 0.57 0.63 -0.013 YIBL

Table ‎III-7: the permanent GPS sites used to determine the Arabian reference frame and Eular pole of rotation, and their horizontal velocity components in ITRF05 and Arabia reference frames and the uncertainties for East and North directions.

The GPS velocity field in Arabian reference frame (Figure III.16) indicates no significant internal deformation (WRMS of residuals motions for Arabia equals to 0.62 mm/yr) in agreement with other geodetic studies in the region (ArRajehi et al., 2010;

Reilinger and McClusky, 2011). Most GPS sites in the Arabian plate have a velocity rate less than the GPS uncertainties (~1 mm/yr) except in the northwest near to the triple junction where the deformation become more complex and many geological structures contribute to the active deformation pattern at the plate boundaries, like the Palmyride fold belt where previous studies suggest shortening rate of ~1 mm/yr (Chaimov et al., 1990; Alchalbi et al., 2010).

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Figure ‎III.16: GPS velocity field of the permanent GPS sites in Arabian plate and around and their 95% confidence ellipses shown in the Arabia reference frame realized in this study.

The northern boundary of the Arabia plate shows a significant left lateral slip rate at the EAF, the same observation can be also made for the DSF. The sites distributed in the Anatolia and Sinai plates have a significant sinistral movement relative to the sites belong to Arabia plate.

The velocity field obtained from our GPS network sites (Figure III.17) suffers a high rate of uncertainty, especially sites in Syria. As it was mentioned before, our GPS sites in Syria were measured twice, during the campaigns of 2009 and 2010, while sites in Turkey have additional measurements during the campaign of 2011 that explains the better uncertainties of sites in Turkey compared with those in Syria. In general, the GPS velocity vectors have uncertainty of 2.42 mm/yr in Syria and 1.92 mm/yr in Turkey. The CGPS sites in Turkey and Syria have better uncertainties with less than 1 mm/yr (e.g., HALB, TUAB in Figure III.17). We notice also that vectors in Syria have abnormal values or directions (Figure

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III.17) which are unexpected in the Arabian reference frame and can be clarified by the insufficient measurements (2 measurements with 1 year of time difference).

Figure ‎III.17: GPS velocity field of the Hatay GPS network and regional permanent stations in Syria and Turkey and their 95% confidence ellipses shown in the Arabia reference frame realized in this study.

Despite the high uncertainty of our GPS velocity field, it offers a good tool to describe the active deformation pattern in the Hatay triple junction and have an assessment of the strain accumulation along major faults in the region as illustrated in Figure III.18. The velocity vectors shown in Figure III.17 and III.16 do not disagree with other velocity rates from other studies (1–2 mm/yr across DSF, 2–3.5 mm/yr across KOF, 3–5 mm/yr across KF and 2–3 mm/yr across the AF, (Gomez et al., 2007b; Meghraoui et al., 2011). A quick and simple interpretation of the GPS velocity field (Figure III.17) and the GPS velocities parallel and perpendicular to major faults in the region (Figure III.19) demonstrate that GPS points located

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in the west of DSF (e.g., AA13, TUAB) have an insignificant southward movement relative to those in the other side of fault. This observation can be carried out after excluding some sites which do not necessarily represent appropriately the plate motion and have a significant error ellipsis (e.g., BB02 in Figure III.17). This leads us to suggest that the DSF does not show significant slip rate along its northern segment and a maximum value can be deduced from the GPS vectors is 1.0-2.0 mm/yr (Figure III.18) which is in agreement with Alchalbi et al., (2010). Comparing the vectors in the east and west of Afrin fault (e.g., DD03, DD05, HALP, DD08 in Figure III.18) and their velocities parallel to the fault in profile 2 (Figure III.19), we can propose a left lateral slip rate value of ~3.0 mm/yr, however it is not totally in agreement with the 4.7±0.7 mm/yr proposed velocity by Meghraoui et al., (2011).

The south-westward motion of Anatolian plate relative to Arabia can be deduced from the vectors of CKVT, PT47, PT01, and ANDT in Figure III.17, which have a maximum velocity of ~10 mm/yr (Figure III.17). Points, like PT05, PT39, and PT31 show a movement rate of 2.0-6.0 mm/yr (Figure III.17) which is half of those of Anatolian plate and the slip rate of EAF. This leads us to conclude that these pointes do not belong to the Anatolian plate. The KOF in this case appears as a plate boundary of Anatolia with a slip rate of ~4.8 mm/yr (profiles 3 and 4 in Figure III.19). The difference in slip rate between KOF and EAF which has ~10.0 mm/yr (McClusky et al., 2000; ArRajehi et al., 2010) leads us to conclude that the KOF in not a segment of EAF.

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Figure ‎III.18 : Illustration of the faults strike-slip rates resulting from our GPS velocity field of the Hatay GPS in Syria and Turkey. GPS vectors and their 95% confidence ellipses are shown in the Arabia reference frame realized in this study. Profiles P1, P2, P3, and P4 are shown in Figure III.19.

Furthermore, an equivalent observation is possible for the velocity vector of points east and west of the Karasu Fault, the points around the KF show similar south-east direction with a significant difference between points in the west of KF (PT24, PT33) and those in the east (PT26,PT34) (Figure III.17), the relative difference suggests a small component of left- lateral strike-slip with a compressional component of 2.0-5.0 mm/yr (See Figure III.19, Profile 3), this assumption contradicts with previous studies suggesting extensional behavior (e.g., Reilinger et al., 2006).

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Figure ‎III.19 : Plots showing the GPS velocities parallel (Right) and perpendicular (left) to the main faults in the Hatay triple junction region. The location of the profiles is shown in Figure III.18.

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