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Probabilistic Seismic Hazard Assessment for the Republic of

EXPLANATORY NOTE

for the Seismic Zonation Map at the Scale of 1:500,000 Based on the Probabilistic Seismic Hazard Assessment for the Republic of Armenia

PROJECT# 7179350

Probabilistic Seismic Hazard Assessment for the Republic of Armenia

EXPLANATORY NOTE

FOR

The Seismic Zonation Map at the Scale of 1:500,000 Based on the Probabilistic Seismic Hazard Assessment for the Republic of Armenia

2018

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Table of Contents

Probabilistic Seismic Hazard Assessment for the Republic of Armenia ...... 1 Introduction ...... 3 Sources and Methodology ...... 4 1. Active fault Analysis ...... 4 2. Map of earthquake source zones with maximum magnitude of seismogenic zones and earthquake recurrence intervals ...... 15 3. Different seismo-tectonic models considered and the selected seismo-tectonic model...... 16 4. List of materials and technologies used for compilation of new seismic zonation map ...... 17 REFERENCES ...... 20 ANNEX 1.Schematic Seismic Zonation Map ...... 22 ANNEX 2.Settlements in the Republic of Armenia by Seismic Zones ...... 23 ANNEX 3.Methodology of Fault Parameter Estimation ...... 27

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Introduction

The seismic zonation map of the area of the Republic of Armenia (RA) at the scale of 1:500,000 was prepared by the Consortium of AIR Worldwide Corporation (USA), GEM Foundation (Italy) and GEORISK Scientific Research CJSC (Armenia) under the Project # 7179350 “Probabilistic Seismic Hazard Assessment for the Republic of Armenia” supported by the World Bank. The results produced by the probabilistic seismic hazard assessment were used for the preparation of the map covering the area of the RA and 150 km in the radius from the state boundaries. In the course of Project implementation, probabilistic seismic hazard computations were realized for 0.5%, 1%, 2%, 10% and 20% probabilities of peak horizontal ground acceleration (PGA) exceedance in 50 years, and 10% exceedance probability in 10 years. This corresponds to the return periods of 10000, 5000, 2475, 475, 225, and 95 years, respectively. Also, as recommended by the Intergovernmental Working Group, the hazard was computed additionally for the 5% PGA exceedance probability in 50 years, as well as for the PGA exceedance probabilities of 5% and 10% in 75 years, which corresponds to the return periods of 975, 1462, and 712 years, respectively. This range of return periods covers the hazard levels proposed by the majority of seismic building codes applicable to the different type of facilities. The following products are delivered: 1. “Seismic Hazard Map of the Territory of the Republic of Armenia at the scale of 1:500,000” The Seismic Hazard Map of the Territory of the Republic of Armenia at the scale of 1:500,000 was prepared by probabilistic assessment for 500 m/s velocity of shear wave propagation in soils and 475 year return period of given intensity earthquakes, corresponding to a 90% probability of non-exceedance of the given intensity in 50 years. The Seismic Hazard Map of the Territory of the Republic of Armenia at the scale of 1:500,000 was submitted as color printed map in its original scale, separately in Armenian and in English. 2. “Seismic Zonation Map of the Territory of the Republic of Armenia at the scale of 1:500,000”. The Seismic Zonation Map of the Territory of the Republic of Armenia at the scale of 1:500,000 was prepared based on the 1:500,000 probabilistic seismic hazard map for 475 year return period for given intensity earthquakes, corresponding to a 90% probability of intensity (PGA) non-exceedance rate in 50 years. According to the seismic zonation map, the area of the RA is subdivided into 3 zones in the ascending intensity order (I, II and III), which cover, correspondingly, 50%, 40% and 10% of the entire area of the RA. In the limits of Zones I, II and III, expected PGA values are expressed in fractions of g (gravity) and correspond 0.3g, 0.4g, and 0.5g, respectively. In the meantime, some suggestions and recommendations provided by the Intergovernmental Working Group, established by the RA Emergency Situations Minister’s Decree N374-A of April 18, 2016, and by the authors of the currently effective RA 11-6.02-2006 Building Code on “Earthquake Resistant Construction: Design Codes” were also considered when drawing contours of the zones. For large cities, computation results for the 90% of PGA non-exceedance probability in 75 years for the given intensity earthquake return period of 712 years were studied and considered additionally. Based on the analysis of the data, certain adjustments were introduced into the boundaries of the seismic zones (see Annex 1). In particular, considering the results of computational data analysis, the city area was fully encompassed within Seismic Zone II The final “Seismic Zonation Map” is submitted as color printed map in its original scale, separately in Armenian and in English. In addition, by the recommendation of the Intergovernmental Working Group and the authors of currently effective RA 11-6.02-2006 Building Code, the Consortium produced a black-and-white version of the seismic zonation map to be incorporated directly in the “RABC-II-6.02-Seismic Engineering Norms ” Building Code of the RA. The map was prepared based on simplified graphics for the A4 format in Armenian and in English (see Annex 1). The map is supplemented by the alphabetically ordered summary list of cities in the RA with an indication of settlements grouped by Marzes along with their assignment to a specific seismic zone (see Annex 2). 3. The digital database in GIS format including all probabilistic seismic hazard computations indicated above. The GIS database of all digital data and all probabilistic seismic hazard computations

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Sources and Methodology

1. Active Fault Analysis Objectives: • Identification of active faults and other structural elements based on the analysis of evidence from remote sensing, geomorphology, topography, publications, and from field geological-structural and geophysical investigations; assessment of fault activity and seismic potential. • Creation of database on fault parameters: length, geometry, dip, kinematics, slip rate, etc. • Estimation of Мmax for the identified faults.

Fault Parameters (length, kinematics, slip rates, 3D geometry, and zone width) In order to identify and estimate parameters of the fault source zones, we analyzed the database of active faults, applying the methodological approach of stage-by-stage assessment of the active faults, and paleoseismological properties of the environment and seismic landscape, as proposed in Slemmons and Depolo (1986), Michetti and Hancock (1997), Michetti et al. (1995, 2005) and INQUA Scale 2007, and according to the methodology approach used in the CauSIN project (see Annex3). The main parameters were estimated for all faults shown in Figure 1.1 and Table1.1. Fault lengths and geometries were derived based on the available geological, geophysical, and other maps, and then updated with the remote sensing information and findings of the field studies. At the next stage, fault geometry data were digitized and entered into the GIS database. Potential uncertainties of fault length estimations are listed for all faults in Table 1.2. The size of uncertainty depends on the completeness of our knowledge about a fault, as well as on its length, and varied from ± 2 km for short structures up to ±50 km for faults several hundreds of kilometers long. Fault segmentation was assessed based on the features of geometry, morpho-structure, kinematics and seismic activity. Kinematics (fault mechanism) was assessed for all faults in the database primarily by field observation data and in individual cases supported by the GPS monitoring data, focal plane solutions, and micro-tectonic measurements. Most of the faults within Armenia, Southern Georgia, Eastern , and North-Western appeared to have a strike-slip mechanism of displacement combined with reverse-fault or normal-fault component. Faults bounding the troughs of the Greater Caucasus, or those that developed within the ridge itself were produced mostly by thrust or reverse faulting with a small strike-slip component observed for the oblique structures. The estimates made for the main faults in Armenia considered long-term vertical (and horizontal) displacement, long-term slip rate, maximum length of surface ruptures (SRL), maximum vertical and horizontal сo-seismic offsets, and short-term vertical and horizontal slip rates obtained with the GPS data. As many of the active faults are situated in the neighboring areas of Turkey, Iran, or Georgia, for which no published data on the listed parameters are available, the slip rate database generated under this Project has remained incomplete. Slip rate data are available just for several faults in Turkey, such as the North-Anatolian Fault, the East-Anatolian Fault, and the Chaldran Fault. Any publications available on the studies performed in the areas of neighboring countries were used to fill in the fault parameter database (Tables 1.1 and 1.2).

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Fig. 1.1: Active faults of Armenia and adjacent territories used for development of seismotectonic model (Tables 1.1, 1.2)

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Table 1.1

NEOTECTONIC SYNTHESIS (e.g., a map of capable faults and their segmentation). SEISMIC LANDSCAPE MODEL

set

and

and

rating (m)± (m)± Dip± Up Sid (mm/y)± (mm/y)± Final comments comments Kinematics name and code seismic max. vertical - Long term slip rate Fault activity rating Fault Fault Fault SRL max length (km)± SRL max length horizontal (h) slip rate4 horizontal (h) Seismogenic zones (fault Co segment) namesegment) and code Seismic landscapeSeismic rating Fault TotalFault (km)± length Seismogenic zones (fault) Seismogenic zones (fault) Segment TotalSegment rating Long term vertical (v) and and (v) vertical term Long Short term vertical (v) and horizontal (h) displacement displacement horizontal(h) (v) andoff horizontal(v) (h) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 >1,20±0,1 and 250±30 and 1 PSSF 1 SS Variable Vertical 3,5±0,5 no data >2,4±0,2 no data Y Y Y 2500±100 (oblique) 3,6±0,2 and 250±30 and PSSF 2 SS Variable Vertical 2,4±1 no data 7,2±0,2 1,6±0,9 Y Y Y

PSSF 2500±100 (oblique)

3,6±0,2 and PSSF 250±30 and Y

Syunik PSSF3 SS Variable Vertical 2,4±2 no data 7,2±0,2 1,6±0,9 Y Y Y

- (Sev/Siun) 2500±100 (oblique) 322±50 PSSF 4

Sevan R/SS N 60-70 N no data no data no data no data no data H H H - (MT) PSSF 5 T/SS N 40-50 N no data no data no data no data no data H H H (MT) Pambak PSSF 6 T/SS N 40-50 N no data no data no data no data no data H H H (MT) PSSF 7 no data and SS Variable Vertical 1±0,2 no data no data 1,3±0,9 Y Y Y (Sev) 800±50

1Ratings assigned to assess the reliability of evidence used to identify active faults and their parameters: (Y) –Yesfor Definitive Evidence; (H) – High for Strong Evidence; (L) –Low for Weak Evidence; (N) –No Evidence

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Table1.1 (continued)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 >=1,8±0,1 and S -

PSSF 8 no data and SS Variable Vertical 1,3±0,1 no data 2,4±0,2 1,3±0,10 Y Y Y (Sev-Hon) 230±30 (oblique) Sevan PSSF

- 2,6±0,2 and PSSF 9 SS Variable Vertical no data 1,3±0,1 no data >4±0,3 1,3±0,11 Y Y Y yunik (Siun)

Pambak (oblique) 2,15±0,3 and 15±2 and GF 1 SS/R Variable Vertical 3±0,5 37.0 2,9±0,3 2±0,4 Y H Y 200±50 (oblique) 2,15±0,3 and 15±2 and GF 2 SS/N Variable Vertical 3±0,5 no data 2,9±0,3 2,6±0,4 H L L 200±50 (oblique) GF 205±40 Y 1,8±0,2 and Gf 3 SS/N Variable Vertical no data 3±0,5 no data 2,5±0,3 no data Y Y Y (oblique) GF 4 SS/N Variable Vertical no data 3±0,5 no data no data no data H Y L GF 5 SS/N Variable Vertical no data no data no data no data no data L H H JaF1 SS/R S Vertical no data no data no data no data no data Y Y Y JavakhqJaF JaF2 77±20 SS/N Variable Vertical no data no data no data no data no data Y Y Y Y Ja F3 SS/R S Vertical no data no data no data no data no data Y Y Y

GhiratakhGir GirF1 N/SS E 75±5 W no data no data no data no data no data L H H 90±20 H F GirF2 R/SS N 65±5N no data no data no data no data no data L H H

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Table 1.1 (continued)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DebF1 SS/N E Vertical no data no data no data no data no data L H H DebF2 SS/N E Vertical no data no data no data no data no data L H H DebakliDebF DebF3 84±20 R/SS E 75±5 E no data no data no data no data no data L H H H DebF4 R/SS E 75±5 E no data no data no data no data no data L L L

DebF5 R/SS W 75±5 E no data no data no data no data no data L L L AhF1 SS E Vertical no data no data no data no data no data H L H

AkhourianAh AhF2 SS no data Vertical no data no data no data no data no data H L L 181±40 H/L F AhF3 SS no data Vertical no data no data no data no data no data H L L AhF4 SS no data Vertical no data no data no data no data no data H L L GSF1 SS/R no data Vertical no data no data no data no data no data H L L GSF2 SS/R Vertical GailatuSiah- no data no data no data no data no data no data H L L Cheshmeh GSF3 SS/R no data Vertical no data no data no data no data no data H L L North Tabriz 345±50 H/L NMF SS/R no data Vertical no data no data no data no data no data H L L GSNTF SF SS/R no data Vertical no data no data no data no data no data H L L NTF SS/R no data Vertical no data no data no data no data no data H L L IgF1 SS/N no data Vertical no data no data no data no data no data H L L Igdir IgF2 SS/N no data Vertical no data no data no data no data no data H L L 123±20 IgF H/L IgF3 SS/N no data Vertical no data no data no data no data no data H L L IgF4 SS/N no data Vertical no data no data no data no data no data H L L

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Table1.1 (continued)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ChF1 SS/R no data Vertical no data no data no data no data no data H L L Chaldran ChF2 208±40 SS/R Vertical ChF no data no data no data no data no data no data H L L H/L ChF3 SS/R no data Vertical no data no data no data no data no data H L L SardarapatSa SaF 46±5 R N 65±5N no data no data no data no data no data L Y N L/N F Yerevan YF YeF 19±3 R N 65±5N no data no data no data no data no data H N L L TashtunTshF TshF 78±20 SS/N Variable Vertical no data no data no data no data no data L H H H

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Table 1.2 SEISMOTECTONIC SYNTHESIS AND MODEL (maximum potential earthquake: source parameters)

) used )

max

M

σ

(length) max PD ) ) PD max

Wells, w ) max (length) max max (equation) ± ( Dipping mean Evidence

by instrumental Kinematics

w name and code Evidence (Mw) by paleoseismological M Sigma M Sigma M max

Sigma M Coppersmith, 1994 Coppersmith, 1994 M Segment length (km) ± (km) length Segment max mean Coppersmith, 1991 McCalpin, 1996; Wells, McCalpin, 1996; Wells, Evidence (M Seismogenic zones (fault segment) namesegment) and code Seismogenic zones (fault) Seismogenic zones (fault) w Fault Total length (km) ± TotalFault (km) length (Cop.91; Wcop,94) Mmax Wcop,94) (Cop.91; M Mmax. by archeo/historical archeo/historical by Mmax. Arithmetical Mean Resulting Arithmetical in seismic hazard calculations seismicin hazard calculations M Standard deviation ( 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 PSSF 1 50±5 SS Vertical 5.6 7.1 0.05 7.1 0.05 0.28 7.1 0.6

PSSF 2 75±5 SS Vertical 7.3 5.4 4.1 7.3 0.03 7.3 0.03 0.28 7.3 0.6

PSSF3 80±5 SS Vertical 7.3 6.1 4.6 7.2 0.03 7.3 0.03 0.28 7.3 0.6

PSSF 4 (MT) 52±10 R/SS 60-70 N 4.5 7.0 0.10 7.1 0.10 0.28 7.1 0.6 PSSF Pambak-Sevan- (Sev/Siun) PSSF 5 (MT) 135±10 T/SS 40-50 N 7.5 5.5 7.5 0.04 7.6 0.04 0.28 7.6 0.6 PSSF 322±50 PSSF 6 (MT) 87±10 T/SS 40-50 N 7.3 5.5 7.3 0.06 7.3 0.06 0.28 7.3 0.6

PSSF 7 (Sev) 66±5 SS Vertical 6.0 4.7 7.1 0.04 7.2 0.04 0.28 7.2 0.6

PSSF 8 86±5 SS Vertical 7.3 7.3 4.1 7.3 0.03 7.3 0.03 0.28 7.3 0.6 (Sev-Hon)

PSSF 9(Siun) 88±10 SS Vertical 7.3 3.9 7.3 0.06 7.3 0.06 0.28 7.3 0.6

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Table1.2 (continued)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 GF 1 56±5 SS/R Vertical 7.1 6.9 7.1 0.05 7.1 0,04 0.28 7.1 0.6 GF 2 84±5 SS/N Vertical 6.9 6.5 3.9 7.3 0.03 7.3 0,03 0.34 7.3 0.6 Garni 205±40 Gf 3 69±5 SS/N Vertical 7.0 5.1 7.2 0.04 7.2 0,04 0.34 7.2 0.6 GF GF 4 60±5 SS/N Vertical 6.6 5.1 7.1 0.04 7.1 0,04 0.34 7.1 0.6 GF 5 45±5 SS/N Vertical 3.8 6.9 0.06 7.0 0,05 0.34 7.0 0.6 Javakhq 77±20 Ja F 77±20 SS/R Vertical 5.9 6.8 0.16 6.8 0,15 0.28 6.8 0.6 JaF

GhiratakhGirF 90±20 GirF 90±20 N/SS 70-80 W 6.5 5.8 7.1 0.09 7.2 0,10 0.34 7.2 0.6

DebakliDebF 84±20 DebF 84±20 SS/N Vertical 6.4 5.1 6.8 0.08 6.8 0,08 0.34 6.8 0.6 AhF1 62±5 SS Vertical 6.0 4.4 7.2 0.04 7.2 0,04 0.28 7.2 0.6 AhF2 21±5 SS Vertical 3.8 6.5 0.13 6.6 0,12 0.28 6.6 0.6 AkhourianAhF 181±40 AhF3 43±5 SS Vertical 6.1 6.3 7.0 0.06 7.0 0,06 0.28 7.0 0.6 AhF4 48±5 SS Vertical 6.8 5.2 7.0 0.05 7.0 0,05 0.28 7.0 0.6 GSF1 118±10 SS/R Vertical 7.4 5.5 7.4 0.04 7.5 0,04 0.28 7.5 0.6 GSF2 122±10 SS/R Vertical 5.5 5.9 7.5 0.04 7.5 0,04 0.28 7.5 0.6 GailatuSiah-Cheshmeh GSF3 105±10 SS/R Vertical 6.2 5.0 7.4 0.05 7.4 0,05 0.28 7.4 0.6 North Tabriz 345±50 NMF 105±10 SS/R Vertical 7.3 4.9 7.4 0.05 7.4 0,05 0.28 7.4 0.6 GSNTF SF 110±10 SS/R Vertical 7.4 5.1 7.4 0.05 7.4 0,04 0.28 7.4 0.6 NTF 144±10 SS/R Vertical 7.6 5.1 7.5 0.04 7.6 0,03 0.28 7.6 0.6

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Table1.2 (continued)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 IgF1 20±2 SS/N Vertical 6.1 4.9 6.5 0.05 6.6 0.05 0.34 6.6 0.6

Igdir IgF2 28±2 SS/N Vertical 3.8 6.8 0.04 6.8 0.03 0.34 6.8 0.6 123±20 IgF IgF3 36±2 SS/N Vertical 6.5 4.3 6.8 0.03 6.9 0.03 0.34 6.9 0.6 IgF4 34±2 SS/N Vertical 5.5 3.8 6.9 0.03 6.9 0.03 0.34 6.9 0.6 ChF1 82±5 SS/R Vertical 7.0 7.1 7.3 0.03 7.3 0.03 0.28 7.3 0.6 Chaldran 208±40 ChF2 44±5 SS/R Vertical 5.7 5.1 6.9 0.06 7.0 0.06 0.28 7.0 0.6 ChF ChF3 60±5 SS/R Vertical 6.0 5.9 7.1 0.04 7.1 0.04 0.28 7.1 0.6 SardarapatSaF 46±5 SaF 46±5 R 60-70 N 5 4.6 6.9 0.06 7.0 0.06 0.28 7.0 0.6

Yerevan 33±2 YeF 33±2 R 60-70 N 6.0 5.5 6.8 0.07 6.8 0.08 0.28 6.8 0.6 YF

Tashtun 78±20 TshF 78±20 SS/N Vertical 7.2 4.9 7.2 0.03 7.2 0.03 0.28 7.2 0.6 TshF

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No data is available on long-term slip rate for the near-regional faults as these structures have absolutely no manifestation in the morphological structure or surface geology. Moreover, GPS observations along these faults during more than 10 years have not established any displacement. Therefore, some of the near-zone faults were assigned low estimates. This applies to the Yerevan Fault and Sardarapat Fault. Table 1.3presents a re-assessment of activity for these two faults: The re-assessment by means of an alternative scale again, like the assessment using Savy and Foxal method (see Annex3), yielded quite low weight-values for the Yerevan Fault and Sardarapat Fault.

Table 1.3: Re-assessment of fault activity for the Yerevan Fault and the Sardarapat Fault

SaF YF Criterion (order of importance) Pro Con Est Pro Con Est Instrumental large earthquake M=6 and above (1) N N Paleoseismology (Displ. From earthquakes) (1) No data No data Archaeo-seismology (displacement, in digs)(1) N N Fault trace - Holocene (any displacement) 10,000 years (1) L N - Quaternary displacement: 1.8 million years (2) L N - Morphology (3) L N Geodetic - Leveling (2) No data No data - GPS (3) Н H Historical large eq. (macroseismicity) (4) H L 0.33 Archaeoseismology(4) N N Microearthquakes(M=0 to M=5) (5) L Y 0.33 Geophysics - Seismic refraction (5) No data No data - Seismic tomography (5) No data No data - Seismic reflection (5) N No data - Gravity (6) N Y 0.17 - Magnetic (6) N No data - Heat flow (6) N No data Remote sensing (5) Y 0.33 N DEM (5) Y 0.33 N Hydrology - groundwater barriers (6) Y 0.17 N - springs etc. (6) Y 0.17 N Conclusion 0.33 0.33

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Any evidence on three-dimensional (3D) fault geometry was incorporated in the seismotectonic model to the extent possible. Tables 1.1 and 1.2present information about the direction of fault plane dipping and on the uplifted wall for most of the faults. In the majority of cases, resolution capacity of the geophysical evidence is sufficient to determine the 3D geometry of the fault plane. The magnetotelluric (MT) survey data for the southeastern part of the Pambak-Sevan Fault demonstrate the clear flower-type structure of fault planes on both sides of the Syunikpull-apart basin. A surface rupture (SRL=37 km, a reverse fault in combination with right-lateral strike-slip) was generated within the triangular pull-apart basin formed between the Garni Fault and the Pambak-Sevan fault as a result of the 1988 earthquake (Мw= 6.9). On the surface, the rupture was verging toward the Pambak-Sevan Fault (N60°), but at the depth of 8 km, according to epicenter distance calculations, it had more gentle inclination of N45°, and became sub-vertical at greater depths, apparently joining the plane of the Pambak-Sevan Fault. Field surface surveys of fault plane geometry (as many measurements as possible), as well as fault plane solutions, were considered for determination of 3D fault geometries. Coupled with fault plane solution, fault plane geometry projected onto the relief enabled us to conclude on the likely deep 3D geometric pattern of the structure. Most of the strike-slip faults in Armenia, Turkey, and Iran demonstrate sub-vertical dip of the plane with alternating uplifts of the opposite walls and helicoidal curving of the fault plane. At the place of the junction between segments of the same fault or between two faults, plane dip angle is reduced and generates clear flower-type structure in near-surface layers within the pull-apart basins. In addition, thrusts and reverse faults of the Greater Caucasus Ridge and some thrusts in Georgia and Armenia have northward-dipping planes. For some of the faults identified in the near region, 3D geometry is still not completely understood. As concerns the Yerevan Fault and the Sardarapat structure, borehole data suggest that they both verge northward at the angles of N50 - 65°. We accepted that a fault zone must be by 15 km wide on both sides of a fault, which was a conservative assumption intended to account for potential uncertainties in the determination of 2D and 3D fault geometries, as well as in the localization of earthquake epicenters, ranging up to ±10 km. In addition, maximum widths of studied fault zones were recorded at the sites, where they formed structures of pull-apart basin type. The width of such pull-apart structures in the regions of the depression and Syunik is 4 km, and 6 km, respectively.

Mmax estimation Various methodological approaches were used to estimate maximum magnitudes for the identified fault source zones. Maximum magnitudes accounted for were derived by the paleo-seismicity (co-seismic displacements) and archaeo-seismicity (offsets of archaeo-structures), historical and instrumental data, as well as by calculations based on the estimated active fault parameters. In the meantime, if Мmax estimates derived by calculations appeared lower than the magnitudes observed for the historical, archaeo-seismic, or paleo-seismic events, the observed values were adopted.

Мmax calculations were conducted by means of empirical relations of Coppersmith (1991) and Wells and Coppersmith (1994). Arithmetical mean value of the derived Mmax estimates was accepted as the resulting one, with an account of standard deviation as proposed in Wells and Coppersmith (1994) (see Table 1.2). For instance, moment magnitude estimation by the method of Hanks and Kanamori (1979) was applied for the calculation for Segment 1 (GF1) of the Garni Fault. An earthquake that occurred on this segment of the Garni Fault in 1988 generated a 37 km-long surface rupture with an average displacement of about 1 meter. The calculations yielded maximum moment magnitude value of 6.76,

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which is lower compared to the estimates made for the GF1 segment by the formulas of Coppersmith (1991) and Wells & Coppersmith (1994) (Мw=7.1). In part, this can be explained by our conservative assumption of the entire segment length for the SRL. The empirical relations of Coppersmith (1991) and Wells & Coppersmith (1994) were chosen to keep to the adopted conservative approach and to provide greater reliability of the derived Мmax estimates.

In Table 1.2, we demonstrate the results of final estimation of Мmaxvalues and of fault geometry and kinematic parameters for fault source zones.

2. Map of earthquake source zones with a maximum magnitude of seismogenic zones and earthquake recurrence intervals The seismic source model developed for the zonation map is based on a combination of characteristic earthquake and gridded seismicity models to take advantage of the detailed knowledge of the known faults while acknowledging the distributed deformation and regional tectonic environment of the Arabian Plate collision zone. The most up-to-date information on historical earthquake data, active faults, strain rates and moment rates from kinematic modeling of GPS data, and from other geologic and geophysical research was used to develop the seismicity source model.

The historical-instrumental seismicity catalog was constructed by merging the earthquake catalogs and information from several sources. The primary source of the historical and recorded instrumental earthquakes is the group of events that occurred within and near Armenia. These events include instrumentally recorded events down to magnitudes 2.0, large historic events dating back to 100 CE and some paleoseismological events. The merged catalog (the historic catalog) was based on the declustered historic catalog identified using Gardner and Knopoff’s (1974) method.

The project Earthquake Source Model consists of 4 depth layers: a shallow crustal layer from the surface to a depth of 25 km and 3 deep layers in the depth range of 25 –50, 50 – 80, and 80 – 160 km, respectively. The 26 seismic source zones in the shallow layer were delineated based on all available geological and geophysical data, including historic seismicity, active faults, geological and geophysical boundaries, and variation of crustal deformation rate and style. The size of each source zone was set large enough to enclose known major active faults or to have sufficient historic seismicity so that the a-and b-values of the GR distribution can be reliably estimated. For each source zone, the rate of seismicity above certain magnitude threshold (4 to 4.5 in general) and the b-value were estimated from the historical earthquake data using the Weichert (1980) method. The upper bound magnitude for the GR distribution was set to approximately equal to the smallest characteristic earthquake magnitudes modeled on faults in each zone. This upper boundary magnitude generally ranges from 6.8 to 7.1 for zones with active fault data. For zones without fault data or in the case the fault data were considered incomplete, a large upper bound magnitude (up to 7.5) was used.

For each seismic source zone in the shallow layer, the rate of seismicity from the historic catalog, fault slip rates, and tectonic moment rate from the kinematic model were integrated to construct the total magnitude-frequency distribution in each seismic source zone. The magnitude-frequency distribution in each source zone was modeled as a combination of the general Gutenberg-Richter distribution (GR distribution) and characteristic earthquake distribution. The partition between GR distribution and characteristic earthquake distribution depended on the available fault data, a total tectonic moment in the zone, and the rate of historic seismicity. Seismicity in the deep layers is modeled using the gridded smooth seismicity approach. For each zone in the deep layers, the seismicity is formulated using the

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Gutenberg-Richter (GR) magnitude concept and is defined in terms of a- and b- values and upper bound magnitudes of the GR distribution.

The spatial distribution of seismicity within each seismic source zone is formulated using the smooth seismicity concept based on the magnitudes and locations of earthquakes in the historic/instrumental catalog in the deep layers. The spatial distribution of seismicity within each seismic source zone in the shallow layer is also formulated using the smooth seismicity concept but instead is based on a weighted combination determined from locations of faults contained in the project input database, locations of earthquakes in the historic/instrumental catalog, and from the uniform rate seismicity computed for each source zone.

3. Different seismo-tectonic models considered and the selected seismo-tectonic model Two fault data sets were collected and used to model fault sources. The first fault dataset contains detailed information about evidence of recent fault movement, historic and prehistoric earthquake ruptures, and slip rate estimation for all major faults located within Armenia (see e.g., Karakhanyan et al, 2016). These data are a part of the input databases developed specifically for this Probabilistic Seismic Hazard Assessment of the Republic of Armenia project. The second dataset was constructed from the fault sources covering the Middle East region by EMME14 (Earthquake Model of Middle East). The fault sources used in EMME14 capture most of the active fault traces in the first dataset, but do not have fault slip rates documented for each fault source. Instead, EMME14 documented the magnitude-frequency distribution along with other information such as fault geometry for each modeled fault source. From the magnitude-frequency and fault geometry information, it is possible to infer the equivalent seismic moment rate and equivalent fault slip rate for each fault used in EMME14. It was established that the equivalent fault slip rates inferred from EMME14 seismicity model were reasonably consistent with the slip rates reported in the project fault database for those few faults that have slip rate information in Armenia. However, EMME14 does not have much detailed documentation on the sources of the slip rate information used to constrain its seismicity model. Therefore, the inferred equivalent slip rates were considered to have large uncertainties and were used along with the moment rates calculated from kinematic modeling and historic seismicity to determine the seismicity rate along faults.

For the major faults where the slip rate information is well documented, the characteristic model was at least partially applied to model the seismicity along the faults. The slip rate inferred from the EMME14 model was not strictly used unless the rate was independently verified in other publications. Based on the distribution of faults with well-documented slip rates, the shallow source zones were divided into two types. The first type of source has relatively good fault data with solid evidence of recent activity and fault slip rate estimation. This type of source zones is mainly in Armenia and its close vicinity (i.e., zones 103, 104, 106, 108, 109, 110, 111, 117,122, and 125 shown in Figure 1.2). The second type of source mainly contains the fault data from EMME14 (see Figure 1.2).

For the first type of source, the slip rate information was directly used to model seismicity along the faults using the characteristic model. For the second type of source zone, the total seismic moment rate of the zone was used to scale the seismicity rate of characteristic earthquakes along each fault of the zone. The rate of characteristic earthquakes along each fault was first calculated from the inferred slip rate of the fault. The total moment rate from the summation of moment rate of each individual fault and the background seismicity was then compared with the total seismic moment rate of the zone to calculate the scaling factor to adjust the seismic rates along all faults in the zone.

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For all major active faults, cascading scenarios that include multi-segment/fault ruptures with earthquakes that can rupture any part of the multiple segment fault zone were considered. The moment-rate partition between single fault and multi-fault ruptures were determined based on the magnitude-frequency distribution indicated by historical data in each seismic source zone, paleoseismological information and the balancing of moment rate.

Figure 1.2: Distribution of active fault data and seismic source zones. The sources zones, represented by blue polygons are delineated to capture the seismicity from the surface to 25 km depth. The fault traces, colored coded by fault slip-rates in mm/a, are based on geological and geophysical information obtained from the project input datasets. EMME fault traces locations (black) and magnitude-rate information were extracted from the EMME fault source model.

4. List of materials and technologies used for compilation of new seismic zonation map The GIS database was applied to prepare the final seismic hazard and zoning maps of the RA.The list of digital layers and information on layer content is presented in Table 1.4. Any geospatial data used in the digital maps are consistent with the OGC (Open Geospatial Consortium) standards. Vector layers of the digital maps are represented by SHP format files, and raster layers are represented by GeoTIFF format files. Databases and tables are presented in the CSV (Comma-Separated Values) text format. Relevant SLD format files, created for each layer, provides for the formation of the layer in the GIS environment. The presented layers are all accompanied by metadata corresponding to the ISO 19115: Geographic information –Metadata standard and contain data description, information on creation time, accuracy, credibility, and limitations, as well as copyright and contact information.

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Table 1.4: GIS database layers and brief description of layer contents. Layer Name Description Seismogenic_faults.shp Active faults in Armenia and adjacent areas, with individual segments, indicated

The layer was established based on the geological and geophysical data, which were later supplemented by the analysis of remote sensing data and results provided by field surveys. Attached to the layer, the database includes the following information: • NameArm –fault name in Armenian • NameEng–fault name in English • Code – segment code • Length – segment length and accuracy rate, in km • M max – potential maximum earthquake magnitude generated by the segment Seismic_hazard_475.tif Map of mean PGA expected in Armenia and adjacent areas with return period in 475 year Raster layer at the resolution of ∼250 m ×250 m, each point of which has the value reflected in decimal shares of acceleration (g). The map is calculated for reference soil condition of 500 m/s and the return period of 475 years, which corresponds to 10% of probability of PGA exceedance in 50 years. The calculation was performed using OpenQuake software toolkit developed by GEM.

Seismic_hazard_475. shp Map of isolines of the mean PGA accelerations expected in Armenia and adjacent areas with return period in 475 year Vector map separated at 0.1 g interval sections; it was produced from the raster acceleration layer by means of calculations in GIS. Attached to the layer, the database includes the following information: • Object ID – object number • PGA Interval – acceleration interval at the accuracy rate of 0.1 g • ShapeArea – seismic zone area (km2) Seismic_hazard_712.tif Map of mean PGA expected in Armenia and adjacent areas with return period in 712 year Raster layer at the resolution of ∼250 m ×250 m, each point of which has the value reflected in decimal shares of acceleration (g). The map is calculated for reference soil condition of 500 m/s and the return period of 712 years, which corresponds to 10% of probability of PGA exceedance in 75 years. The calculation was performed using OpenQuake software toolkit developed by GEM.

Seismic_hazard_712. shp Map of isolines of the mean PGA accelerations expected in Armenia and adjacent areas with return period in 712 year Vector map separated at 0.1 g interval sections; it was produced from the raster acceleration layer by means of calculations in GIS. Attached to the layer, the database includes the following information: • Object ID – object number • PGA Interval – acceleration interval at the accuracy rate of 0.1 g Hazard_map_mean.csv A table in CSV format, containing all seismic hazard computation options provided for in the TOR. The resulting maps were presented in three Technical Interim Reports and in the Final Report.

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Layer Name Description Seismic Zones.shp Seismic zoning map of Armenia Complex vector map prepared on the basis of Seismic_hazard_475. shp and Seismic_hazard_712. shp considering the recommendations of the Intergovernmental Working Group and authors of the Building Code of the RA. Attached to the layer, the database includes the following information: • PGA Interval – acceleration interval at the accuracy of 0.1 g; • Seismic Zone – seismic zone corresponding to the acceleration interval; • ShapeArea – seismic zone area (km2) Border50.shp The national border of the Republic of Armenia Linear vector layer created in GIS by digitizing the USSR Headquarters topography maps at the scale of 1:50,000 (implemented by “GEORISK Scientific Research” CJSC ).

Settlements. shp Map of settlements of the Republic of Armenia Vector point map that encompasses any settlement in the RA that has a population of more than 2000 according to the census of 2011 (source – National Statistical Service of the RA, NSS, www.armstat.am). Attached to the layer, the database includes the following information: • CodeArmStat – settlement code as per NSS • NameArm – settlement name in Armenian • NameEng– settlement name in English • NameRus– settlement name in Russian • Marz – marz code as per NSS • Type – settlement type (0 – capital; 1 – the center of marz; 2 – town; 3 – other settlements) • Population – population number • PGA_475 – peak acceleration expected in the settlement according to the seismic hazard map for 475 return period Major rivers.shp Main rivers in the Republic of Armenia Linear vector layer developed in GIS by digitizing the USSR Headquarters topography maps at the scale of 1:25,000 (implemented by “GEORISK Scientific Research” CJSC ).Attached to the layer, the database includes the following information: • NameArm – river name in Armenian • NameEng – river name in English • WOC – unique code of the given river section according to the ERICA coding system • ShapeLength – the length of the given river section (km) Big_Lakes.shp Largest water bodies in the Republic of Armenia (lakes and water reservoirs) • NameArm –name in Armenian • NameEng –name in English • WOC – unique code of the given water body according to the ERICA coding system • ShapeArea –area of the given water body (km2) Hill_Armenia45m.tif Relief of the area of the Republic of Armenia Shaded terrain raster layer at the resolution of 45 m, developed in GIS from the digital elevation model of the US satellite radar survey, SRTM DEM (source - ftp:\\e0srp01u.esc.nasa.gov/srtm/version2/SRTM/3):

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REFERENCES

Abrahamson N, Nicholas G, Kofi A (2016). BC Hydro Ground Motion Prediction Equations for Subduction Earthquakes, Earthquake Spectra, 32(1): 23-44. Ambraseys N, Jackson J (1998). Faulting associated with historical and recent earthquakes in the Eastern Mediterranean region, Geophysical Journal International, 133(2): 390-406. Balassanian S, Nazaretian S, Avanessian A, Arakelian A, Igoumnov V, Badalian M, Martirossian A, Ambartsumian V, Tovmassian A (1997). The new seismic zonation map for the territory of Armenia, Natural Hazards,15(2-3): 231-249. Bindi D, Massa M, Luzi L, Ameri G, Pacor F, Puglia R, Augliera P (2014). Pan-European ground-motion prediction equations for the average horizontal component of PGA, PGV, and 5 %-damped PSA at spectral periods up to 3.0 s using the RESORCE dataset, Bulletin of Earthquake Engineering, 12(1): 391–430. Cauzzi C, Faccioli E, Vanini M, Bianchini A (2015). Updated predictive equations for broadband (0.01–10 s) horizontal response spectra and peak ground motions, based on a global dataset of digital acceleration records, Bulletin of Earthquake Engineering, 13(6): 1587–1612. Chiou BS-J, Youngs RR (2014). Update of the Chiou and Youngs NGA model for the average horizontal component of peak ground motion and response spectra, Earthquake Spectra, 30(3):1117–1153. Cornell, CA (1968). Engineering seismic risk analysis, Bulletin of the Seismological Society of America, 58(5): 1583-1606. Danciu L, Şeşetyan K, Demircioğlu M, Gülen L, Zare, M, Basili R, Elias A, Adamia S, Tsereteli N, Yalçın H, Utkucu M (2017). The 2014 earthquake model of the Middle East: seismogenic sources. Bulletin of Earthquake Engineering, doi:10.1007/s10518-017-0096-8. Gardner JK, Knopoff L (1974). Is the sequence of earthquakes in southern California, with aftershocks removed, Poissonian?, Bulletin of the Seismological Society of America, 64(5): 1363-1367. Haines AJ, Holt WE (1993). A procedure for obtaining the complete horizontal motions within zones of distributed deformation from the inversion of strain rate data, Journal of Geophysical Research: Solid Earth, 98(B7): 12057-12082. Jenny S, Goes S, Giardini D, Kahle HG (2004). Earthquake recurrence parameters from seismic and geodetic strain rates in the eastern Mediterranean, Geophysical Journal International, 157(3): 1331-1347. Kadirioğlu FT, Kartal RF, Kılıç T, Kalafat D, Duman TY, Azak TE, Özalp S, Emre Ö (2016). An improved earthquake catalog (M≥ 4.0) for Turkey and its near vicinity (1900–2012). Bulletin of Earthquake Engineering, doi:10.1007/s10518-016-0064-8. Kale Ö, Akkar S, Ansari A, Hamzehloo H (2015). A Ground-Motion Predictive Model for Iran and Turkey for Horizontal PGA, PGV, and 5% Damped Response Spectrum: Investigation of Possible Regional Effects. Bulletin of the Seismological Society of America, 105(2): 963–980. Karakhanyan AS, Trifonov VG, Philip H, Avagyan A, Hessami K, Jamali F, Bayraktutan MS, Bagdassarian H, Arakelian S, Davtian V, Adilkhanyan A (2004). Active faulting and natural hazards in Armenia, eastern Turkey and northwestern Iran, Tectonophysics, 380(3): 189-219. Karakhanyan A, Vernant P, Doerflinger E, Avagyan A, Philip H, Aslanyan R, Champollion C, Arakelyan S, Collard P, Baghdasaryan H, Peyret M, Davtyan V, Calais E, Masson F (2013). GPS constraints on continental deformation in the Armenian region and Lesser Caucasus, Tectonophysics, 592: 39-45. Karakhanyan A, Arakelyan A, Avagyan A, Sadoyan T (2016). Aspects of the seismotectonics of Armenia: New data and reanalysis, Geological Society of America Special Papers, 525, pp. SPE525-14. Kreemer C, Blewitt G, Klein EC (2014). A geodetic plate motion and global strain rate model, Geochemistry, Geophysics, Geosystems, 15(10): 3849-3889. Luzi L, Puglia R, Russo E, ORFEUS WG5 (2016). Engineering Strong Motion Database, version 1.0.Istituto Nazionale di Geofisica e Vulcanologia, Observatories & Research Facilities for European Seismology, doi: 10.13127/ESM. Michetti AM, Franck A, Audermard M, and Marco S(2005). Future trends in paleoseismology: integrated study of seismic landscape as a vital tool in seismic hazard analyses, Tectonophysics, 408, pp. 3-51

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Michetti AM, Esposito E, Gurpinar A, Mohammadioun B, Mohammadioun J, Porfido S, Rogozhin E, Serva L, Tatevossian R, Vittori E, Audermand F, Comerci V, Marco S, McCalpin J, and Morner NA (2004). The INQUA Scale: An innovative approach for assessing earthquake intensities based on seismically-induced ground effects in natural environment, in Vittori, E. and Comerci, V, eds., Memorie descriptive della Carta Geologica D’Italia, volume LXVII, Special Paper, APAT, Rome, SystemCart Srl, 116 p. Michetti AM, and Hancock PL (1997) Paleoseismology: Understanding past earthquakes using Quaternary geology, Journal of Geodynamics, volume 24 (1-4), p. 3-10. SlemmonsDB, and dePolo C M (1986). Evaluation of active faulting and associated hazard, Wallace, R.E. (Panel chairman), Active tectonics, Washington, D.C., National Academy Press, p. 45-62 Wells DL, and Coppersmith K J(1994). New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement: Bulletin of the Seismological Society of America, volume 84, no. 4, p. 974-1002 Pagani M, Monelli D, Weatherill G, Danciu L, Crowley H, Silva V, Henshaw P, Butler L, Nastasi M, Panzeri L, Simionato M, Vigano D (2014). OpenQuake Engine: An Open Hazard (and Risk) Software for the Global Earthquake Model, Seismological Research Letters, 85(3): 692–702. Petersen MD, Moschetti MP, Powers PM, Mueller CS, Haller KM, Frankel AD, Zeng Y, Rezaeian S, Harmsen SC, Boyd OS, Field N (2015). The 2014 United States national seismic hazard model, Earthquake Spectra, 31(S1): S1-S30. Reasenberg P (1985). Second-order moment of central California seismicity, 1969–1982, Journal of Geophysical Research: Solid Earth, 90(B7): 5479–5495. Reilinger R, McClusky S, Vernant P, Lawrence S, Ergintav S, Cakmak R, Ozener H, Kadirov F, Guliev I, Stepanyan R, Nadariya M, Hahubia G, Mahmoud S, Sakr K, ArRajehi A, Paradissis D, Al-Aydrus A, Prilepin M, Guseva T, Evren E, Dmitrotsa A, Filikov SV, Gomez F, Al-Ghazzi R, Karam G (2006). GPS constraints on continental deformation in the Africa-Arabia-Eurasia continental collision zone and implications for the dynamics of plate interactions, Journal of Geophysical Research: Solid Earth, 111(B5): B05411. Ritz JF, Avagyan A, Mkrtchyan M, Nazari H, Blard PH, Karakhanian A, Philip H, Balescu S, Mahan S, Huot S, Münch P (2016). Active tectonics within the NW and SE extensions of the Pambak-Sevan-Syunik fault: Implications for the present geodynamics of Armenia, Quaternary International, 395: 61-78. Schwartz DP, Coppersmith KJ (1984). Fault behavior and characteristic earthquakes: Examples from the Wasatch and San Andreas fault zones, Journal of Geophysical Research: Solid Earth, 89(B7): 5681-5698. Stepp JC (1973). Analysis of completeness of the earthquake sample in the Puget Sound area, NOAA Tech. Report ERL 267-ESL30, Boulder, Colorado. Uhrhammer RA (1986). Characteristics of northern and central California seismicity, Earthquake Notes, 57(1): 21. VanStiphout T, Zhuang J, Marsan D (2012). Seismicity declustering, Community Online Resource for Statistical Seismicity Analysis, doi:10.5078/corssa-52382934. Ward SN (1998). On the consistency of earthquake moment release and space geodetic strain rates: Europe, Geophysical Journal International, 135(3): 1011-1018. Weatherill GA, Pagani M, Garcia J (2016). Exploring earthquake databases for the creation of magnitude-homogeneous catalogs: tools for application on a regional and global scale. Geophysical Journal International, 206(3): 1652-1676. Weichert DH (1980). Estimation of the earthquake recurrence parameters for unequal observation periods for different magnitudes, Bulletin of the Seismological Society of America, 70(4): 1337-1346.

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ANNEX 1

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ANNEX 2

Settlements in the Republic of Armenia by Seismic Zones

List of settlements in the Republic of Armenia by seismic zones

Settlement name Seismic zone Settlement name Seismic zone

A. CentersofMarzes (Provinces)

Yerevan II II I II Artashat I I I I II Idjevan I Vanadzor III

B. Important Cities

Aparan II II Talin I II Ararat I II I II I I I I I I II II Sevan II I II Kadjaran II Alaverdi I Agarak II I I Spitak III I II I II Dilidjan II II I

C. SettlementsbyMarzes

1. AragatsotnMarz

Aragats II I Aragatsavan I I I Shamiram I I I Karbi I I Kosh I Udjan I II I I

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Settlement name Seismic zone Settlement name Seismic zone

2. Ararat marz

Azatavan I I I I I I I I Ayntap I Mrgavet I Avshar I I I I Ararat I Norashen I Arbat I I Argavand I Nor Kyanq I Armash I Shahumyan I Geghanist I I I I Dalar I I I I I VerinArtashat I Dvin I I I Urcadzor II I PokrVedi I I Kaghtsrashen I

3. Armavir marz I I I Hatsik I I Sardarapat I Aragats I I Argavand I I Armavir I I I I I Nalbandyan I Baghramyan I I I Voskehat I Gay I Djanfida I Getashen I Djrarat I I I Yeghegnut I I I I I I I I

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Settlement name Seismic zone Settlement name Seismic zone

4. GegharkunikMarz II II I Tsovinar I II II Gandzak I I II Dzoragyugh I II II I NerkinGetashen I I II Tsovasar I I I I I I II I Tsakqar I VerinGetashen I II

5. Lori marz

Arevashogh III Margahovit III Aqori I Metsavan II Gugark III Shnogh I Dsegh II Djrashen III Kurtan II Odzun I

6. marz

Alapars II II Around II II Aramus II Mayakovsky II Argel II III II Nor II II I II Djrvezh II II Solak II Garni II Kaghsi II II II II Kasakh II II

7. Shirak marz

Azatan II I II I I I III Panik I Horom I PokrMantash I II Maralik I

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Settlement name Seismic zone Settlement name Seismic zone

8. Syunik marz

Brnakot I I I I I

9. Vayots-DzorMarz

Getap I Malishka I Gladzor I

10. marz

Azatamut I Berdavan I I I I I I Koti I Achadjur I Koghb I I Haghartsin II I I

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ANNEX3

The methodology of Fault Parameter Estimation

The assessment of fault activity and hazard based on the empirical relationship between slip rates, earthquake magnitude and recurrence interval by Slemmons and Depolo (1986) is presented in Annex3, Figure 1.

Figure 1: Assessment of fault activity and hazard based on the empirical relation between slip rates, earthquake magnitude, and recurrence interval by Slemmons and Depolo (1986)

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Table 1 in Annex3lists thequantitative indicators to evaluate seismic landscape according to Michetti and Hancock (1997), Michetti et al. (1995) and INQUA Scale 2007.

Table 1: Quantitative estimation of seismic landscape according to Michetti and Hancock (1997), Michetti et al. (1995), and INQUA Scale 2007

Seismic Landscape Category INQUA ESI 2007 scale QWF Magnitude (Michettiet al., 1997) (Michettiet al., 2005) (Michettiet al., 2005)

Seismic landscape with surface AA(A) − very high activity XI-XII − environmental faulting, subordinate rate (>10 mm/yr) with effects become decisive for ruptures, sympathetic 0.8-1.0 excellent geomorphic M>∼7 intensity assessment or are ruptures, and secondary evidence as at major plate the only tool for intensity phenomena (e.g.. ground boundaries assessment failure, liquefaction) VIII-X − extensive to Seismic landscape with A− high activity rate (∼1 important and widespread subordinate ruptures, mm/yr) with excellent effects in the environment, 0.6-0.8 sympathetic ruptures, and M>∼6 geomorphic evidence as at becoming increasingly secondary phenomena (e.g.. major plate boundaries critical for intensity ground failure, liquefaction) assessment B—moderate activity (~0.1 Seismic landscape with mm/yr) with moderate to III-VII − marginal to sympathetic ruptures and 0.4-0.6 well-developed M >∼6 appreciable effects on the secondary phenomena (e.g.. geomorphic evidence of environment ground failure, liquefaction) activity C—low activity (<0.01 No discernible seismic mm/yr) with sparse I-III − no perceptible <0.4 landscape geomorphic evidence of environmental effects activity

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Figure 2 in Annex 3demonstrates the process of stage-by-stage assessment of fault activity and seismic potential according to the method of Michetti et al. (2005).

Figure 2: Process of stage-by-stage assessment of fault activity and seismic potentiality according to the method of Michetti et al. (2005)

The empirical relations listed above, along with the technique of stage-by-stage identification of active faults and assessment of their seismic potential, yielded fault activity rate estimates shown in Annex3, Tables 1-4. In the process of stage-by-stage assessment of fault activity and seismic potentiality by Michetti et al. (2005), four grades were assigned to assess the reliability of evidence used to identify active faults and their parameters: • “Yes” for Definitive Evidence – (Y) • “High” for Strong Evidence – (H) • “Low” for Weak Evidence – (L) • “NoEvidence” – (N) These estimates are listed in Tables 2, 3, and 4 below.

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Table 2

BIBLIOGRAPHIC COMPILATION AND CRITICAL SYNTHESIS (Scope: to establish the occurrence of recent deformations and characterize them in space and time)

Fault Name and Code Tectonic Climatic Setting and Stratigraphy Paleontology and Geo- Geophysical and Well- Hydrothermalism Fault Evidence Geomorphology and Sedimentology chronology Evidence logging Evidence Evidence Total Evidence Evidence Rate

Pambak-Sevan-SyunikPSSF Y H L L H L Y GarniGF Y H H H L L Y JavakhqJaF L Y No data No data No data No data Y GhiratakhGirF H L Y H Y H Y DebakliDebF H L H H H H H AkhourianAhF L L No data No data H No data H GailatuSiah-Cheshmeh -North Tabriz GSNTF Y Y H H No data No data Y IgdirIgF Y H H L L No data Y ChaldranChF Y Y No data No data No data No data Y SardarapatSaF N L N N N N L Yerevan YF L N L L H N H TashtunTshF H L Y H Y H Y

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Table 3

SATELLITE IMAGE, AERIAL PHOTO & DEM INTERPRETATION (Scope: to identify and characterize recent (Quaternary) tectonic deformations, earthquake ground effects, and capable faults) and FIELD RECONNAISSANCE (Scope: to incorporate new findings regarding Quaternary faulting, folding, and earthquake ground effects and characterize those in time and space)

Fault Name and Code SATELLITE IMAGE AERIAL PHOTO DEM data FIELD RECONNAISSANCE FAULT TOTAL data data data RATE Pambak-Sevan-Syunik PSSF Y Y Y Y Y GarniGF H H H Y Y JavakhqJaF Y Y Y Y Y GhiratakhGirF Y Y Y Y Y DebakliDebF Y Y Y Y Y AkhourianAhF L No data L L L GailatuSiah-Cheshmeh- North Tabriz GSNTF Y Y Y Y Y IgdirIgF Y No data Y L Y ChaldranChF Y No data Y Y Y SardarapatSaF Y No data Y L Y Yerevan YF N N N N N TashtunTshF Y Y Y Y Y

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Table 4

SEISMOLOGICAL DATA ANALYSIS AND CORRELATION

Fault Name and Code Strong Seismic Events by Strong Seismic events by Strong Seismic events by Earthquake Ground Fault Paleoseismological data Archeoseismological and Historical Instrumental Seismological Total Effects (BC) data (BC/AD) data (AD) Rate Pambak-Sevan-SyunikPSSF Y [7,4; 2200] Y [7,5; XII-IX BC] H [5,5; 1994] H (surface rupture) Y GarniGF Y[7,1; 19000] Y [7; 1679] H [6,9; 1988] H (surface rupture) Y JavakhqJaF no data H [6,3; 1899] H [5,7; 1959] H (surface rupture) H GhiratakhGirF no data H [6,5; 915] H [5,8; 1968] no data H DebakliDebF no data H [6,5; 1931] L [5,1: 1932] no data H AkhourianAhF no data H [6,8: 1924] H [6,3;1935] no data H GailatuSiah-Cheshmeh- North Tabriz GSNTF no data Y [7,7; 1780] L [5,9: 1934] H (surface rupture) Y IgdirIgF no data H [6,5; 641] L [4,3; 1968] no data H ChaldranChF no data Y [7; 1696] Y [7,1;1976] no data Y SardarapatSaF no data N N no data N Yerevan YF no data L [6.0;893] L [5,5; 1937] no data L TashtunTshF no data H [7,2; 1406] N no data H

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Assessment reliability was verified using the system adopted for the CauSIN Project in 2005. The assessment system, proposed by Jean Savy and William Foxal for the CauSIN Project, includes the following statements: “Pro” column is for evidence in favor of the hypothesis -“The fault exists and is active”; “Con” column is for evidence against. Any fault is assessed by the parameters listed in Annex3, Table 5.The evidence supporting a hypothesis that the considered source exists and is active2 can be ranked as follows: • (Y) Definitive evidence. A “Yes” in “Pro” column means the fault is active. A “Yes” in “Con” column means the fault does not exist or is definitely not active. • (H) “High” for strong evidence; • (L) “Low” for weak evidence; • (N)“No evidence”

Table 5: Justification of Source Existence/Activity adopted in the CauSIN Project

Criterion (order of importance) Instrumental large earthquake of M=6 and greater (1) Paleo-seismology (Displ. from earthquakes) (1) Archaeo-seismology (displacement, in digs)(1) Fault trace − Holocene (any displacement) 10,000 years(1) − Quaternary displacement: 1.8 million years (2) − Morphology (3) Geodetic − Leveling (2) − GPS (3) Historical large eq. (macroseismicity) (4) Archaeoseismology (4) Microearthquakes(M=0 to M=5) (5) Geophysics − Seismic refraction (5) − Seismic tomography (5) − Seismic reflection (5) − Gravity (6) − Magnetic (6) − Heat flow (6) Remote sensing (5) DEM(5) Hydrology − groundwater barriers (6) − springs etc. (6) Conclusion

2 Activity is defined here as “has had displacement in the last 20,000 years”. A feature that displays no displacement in this period of time is assumed to have insufficient seismicity to contribute to the total probabilistic seismic hazard.

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In Annex3, Table 6, quantitative weight factors are assigned to the fault assessment criteria suggested by Jean Savy and William Foxal. Any weight value from 0.33 to 1 is conditionally accepted sufficiently to include a fault in the seismotectonic model, while all values below 0.33 would be deemed insufficient to include a fault in the seismotectonic model. The boundary value of 0.33 was selected based on the following considerations. The availability of micro-earthquakes, geophysical anomalies, remote sensing and DEM data, and hydro-geological aspects are assigned weight values ranging from 0.08 to 0.33 and do not determine a conclusion on whether the considered fault is active. Moreover, they might appear to have no relation to a fault, even a passive one. Meanwhile, any weight factor value higher than 0.33 for such criteria as (1) moderate to large M>6, paleo-, archaeo-, historical, or instrumental seismicity, (2) fault displacements during the Holocene and Quaternary periods, (3) morpho-structural features, and (4) GPS observations each can give unambiguous answers about activity of a fault and its earthquake potential.

Table 6: Weight Factors of Fault Assessment Criteria

Large Instrumental earthquake, M=6 and above Y H L NO

Paleo-seismology (Displ. From earthquakes) (1) 1 0.9 0.83 0

Archaeo-seismology (displacement, in digs)(1) 1 0.9 0.83 0

Quaternary Displacement: 1.8 million years (2) 0.83 0.75 0.67 0

Leveling (2) 0.83 0.75 0.67 0

Morphology (3) 0.67 0.6 0.5 0

GPS (3) 0.67 0.6 0.5 0

Large Historical Earthquake (macroseismicity) (4) 0.5 0.42 0.33 0

Archaeoseismology(4) 0.5 0.42 0.33 0

Micro-earthquakes (M=0 to M=5) (5) 0.33 0.25 0.17 0

Geophysics 0.33 0.25 0.17 0

- Seismic refraction (5) 0.33 0.25 0.17 0

- Seismic tomography (5) 0.33 0.25 0.17 0

- Gravity (6) 0.17 0.12 0.08 0

- Magnetic (6) 0.17 0.12 0.08 0

- Heat flow (6) 0.17 0.12 0.08 0

Remote sensing (5) 0.33 0.25 0.17 0

DEM 0.33 0.25 0.17 0

Hydrology 0.17 0.12 0.08 0

- ground water barriers (6) 0.17 0.12 0.08 0

- springs etc. (6) 0.17 0.12 0.08 0

34 PROJECT# 7179350

Mmax estimation methodology

Initially, standard deviations were assessed for the mean arithmetical values σmean, calculated by the formulas of Coppersmith (1991) and Wells and Coppersmith (1994) (see column Sigma of Mmax mean value, of Table 1.2). Then, standard deviation σWC, which is equal to 0.28 and adopted in the formulas of Coppersmith (1991) and Wells, Coppersmith (1994) was added to the derived values.

The final value of σtotalstandard deviation was estimated by the formula:

2 2 1/2 σtotal = (σmean + σWC )

For the calculations, it was assumed that a fault segment always ruptured along the entire length. Rupturing of two segments during a single earthquake has been recorded neither in the palaeoseismological nor in the historical evidence for the territory of Armenia and neighboring countries. Even the series of very strong earthquakes with magnitudes in the range of 7.0-7.7 that occurred in the middle of the 20th century along the North-Anatolian Fault did not demonstrate the possibility of two segments rupturing in the same time.

Additionally, we attempted Мmax calculations by the method of Bonila et al. (1984), but as this formula uses Мs (while we adopted Мw), we had to perform supplementary calculations to convert from Ms to Mw. As the first step, we derived M0 by the relation of Ekstrom G. and Dziewovski A.M. (1998), and then we applied the formula of Hanks and Kanamori (1979). With this approach, the size of uncertainty appeared to be too large and we refrained from using the relations of Bonila et al. (1984).

35 PROJECT# 7179350