JAPAN SOCIETY OF CIVIL ENGINEERS

SITE INVESTIGATION AND ENGINEERINGEVALUATION OF THE VAN EARTHQUAKES OFOCTOBER 23 AND NOVEMBER 9, 2011

Prof. Dr. Ömer AYDAN

Prof. Dr. Reşat ULUSAY

Tokai University, Ocean Research Institute,
Shizuoka, Japan

Hacettepe University, Department of
Geological Engineering, Ankara, Turkey

Prof. Dr. Halil KUMSAR

Prof. Dr. Kazuo KONAGAI

Pamukkale University, Department of
Geological Engineering, Denizli, Turkey

University of Tokyo, Institute ofIndustrial Science, Tokyo, Japan

February 2012

SUMMARY
An earthquake (Van-Erciş earthquake) with a moment magnitude (M w ) of 7.2 and alocal magnitude of 6.7 occurred at 13:41 on local time on October 23, 2011 in the Van
province located in the eastern Turkey. The major energy release occurred within 20
seconds although the total duration of the rupture was about 50 seconds. According tothe official report, the casualties are 604 and the number of injured people is morethan 4000, which were caused by collapsed or damaged residential and commercial
buildings. A number of buildings collapsed particularly in Erciş town (about 60
buildings) and Van (one building). In this earthquake, liquefaction and associatedground deformations were evident and wide spread sand boils were observed
particularly in Erciş Plain and the flood plain of Karasu River at the north of Van city.
17 days after the Van-Erciş earthquake, the region was also hit by another earthquakewith a magnitude of 5.6 (M w ) on November 9, 2011 at 19:23 on local time. Because
the epicenter of this earthquake is located near Edremit, which is a town on theeastern shore of Van Lake about 16 km to the south of Van city centre, the earthquake
is called Van-Edremit earthquake. This earthquake caused the collapse of 25 buildings
in Van city centre. Fortunately, 23 of them had been evacuated due to previous
damage occurred in October 23, 2011 earthquake. The total dead loss and injured
people caused by this earthquake are 40 and 30, respectively. This earthquake also
caused additional damage to some buildings and liquefaction.
In this report, site observations carried out throughout the earthquake region andinformation gathered by the authors are described. This study is an inter-disciplinary
work of various disciplines of science and engineering such as geology, seismology,
tectonics, and geotechnical and earthquake engineering. This investigation was carriedout to cover both engineering and scientific aspects of both earthquakes. In addition totheobservations,evaluations

andpossiblecausesofthedamages,andrecommendations for future earthquakes and lessons learned from these earthquakes
are presented in the report.

iCONTENTS
SUMMARY………………………………………………………………………… i
CONTENTS…………………………………………………………….............…..ii
1. INTRODUCTION…………………………………………………..................1
2. GEOLOGY AND HYDROGEOLOGICAL CHARACTERISTICS
OF THE EARTHQUAKE AFFECTED AREA …………………...........6
2.1. Geology …………………………………………………………...............6
2.2. General Hydrogeological Characteristics of the Earthquake
Region……………………………………………………………………10
3. NEOTECTONICS OF THE EAST ANATOLIAN REGION AND
MAJOR ACTIVE FAULTS IN THE EARTHQUAKE-AFFECTEDAREA …………………………………………………………………….……18
3.1. General Neotectonics of the East Anatolian Region…………………..18
3.2. Major Active Faults in the Earthquake Affected Area…………………20.
4. SEISMICITY OF VAN LAKE REGION……………………………….............27
4.1. Historical Earthquakes………………………………………...............27
4.2. Earthquakes Occurred in the Instrumental Period…………….............28
5. SEISMIC CHARACTERISTICS OF THE VAN-ERCİŞ
EARTHQUAKE AND FAULTING……………………………………………..31
5.1. Earthquake Focal Mechanism and Faulting………………………...…31
5.2. Aftershock Activity……………………………………………………33
5.3. Changes in the Shore Line of Van Lake …………………………..….34
5.4. Surface Ruptures……………………………………………………...36
5.5. Comparisons with Other Turkish and Worldwide Earthquakes……….38
6. STRONG MOTION CHARACTERISTICS ………………...............………….40
6.1. Estimated and Measured Ground Motions and Their
Attenuation…………………………………………………....................40
6.2. Spectral Characteristics of Ground Motions…………………..………45
6.3. Natural Periods of Structures in Turkey……………………………….45
6.4. Permanent Ground Motions from GPS and INSAR…………………..47ii

6.5. Collapse Directions of Simple Structures and estimated strong motions 49
7. DAMAGE TO STRUCTURES …………………………………………..............53
7.2. Mosques and Minarets………………………………………….............53
7.3. Reinforced Concrete Structures………………………………...............54
7.4. Masonry Structures ………………………………………….................58
7.4 Elevated Water Towers and Silos……………………………...............60
7.5. Dams …………………………………………………………................62
7.5 Pre-cast (Prefabrik) Reinforced Concrete Structures……….............63
7.5. Damage to Historical Structures ……...……………………................66
8. DAMAGE TO TRANSPORTATION FACILITIES……………………………71
8.1. Roadways and Roadway Bridges…………………………………...…...71
8.2. Railways………………………………………………………………....77
8.3. Ports and Breakwaters…………………………………………………...79
8.4. Airports……………………………………………………...…………..81
9.

DAMAGE TO LIFELINES………………………………………………...........82
9.1. Electricity………………………………………………………………...........82
9.2. Water Supply and Water Distribution Networks………………………............86
9.3. Natural Gas Network……………………………………………………..........89
9.4. Seewage…………………………………………………………………..........89
9.5. Telecommunications………………………………………………………..…90

10. GEOTECHNICAL ASPECTS OF THE EARTHQUAKE AND
ASSOCIATED GROUND FAILURES AND DAMAGES………………. .........92
10.1. Local Site Conditions………………………………………………………...92
10.2. Liquefaction and Associated Ground Failures……………………………....100
10.2.1 Liquefaction and its effects on structures………..……….........……..100
10.2.2. Lateral spreading and its effects on structures………………………108
10.2.3. Evaluation of liquefaction and lateral spreading…………………….112
10.3. Slope and Embankment Failures ………………………………….………116
11. TRIGGERED VAN-EDREMİT EARTHQUAKE………………………..……120
11.1. Introduction…………………………………………………………...........120
11.2. Focal Mechanism and Seismicity…………………………………………..120
11.3. Characteristics of Strong Motions…………………………………….........122
11.4. Casualties and Structural Damage………………………………………….125
11.5. Geotechnical Aspects and Associated Damages…………………………...129iii

12. CONCLUSIONS AND RECOMMENDATIONS ……………………….…….132
ACKNOWLEDGEMENTS ………………………………………………….…135
REFERENCES…………………………………………………………………..137iv

1. INTRODUCTION
An earthquake with a moment magnitude (M w ) of 7.2 and a local magnitude of 6.7
occurred at 13:41 on local time on October 23, 2011 in the Van province located in the
Eastern Turkey, which was subjected to big earthquakes in the past (Figure 1.1). The
major energy release occurred within 20 seconds although the total duration of the
rupture was about 50 seconds. Boğaziçi University Kandilli Observatory and
Earthquake Research Institute (KOERI, 2011) estimated that the earthquake wascentered at 38.77578 N, 43.3602 E which places the epicenter about 30 km north of the
Van city center at the location of Tabanlı village (Figure 1.2). The earthquake
originated at a depth of ranging between 15-19 kilometers according to the different
institutes and was resulted from the movement of a 50 km long and 20 km wide thrustfault trending about E-W direction between the Van Lake and Erçek Lake at the northof Van. Although the estimated average relative displacement of the fault is more than 2m according to the empirical relation proposed by Aydan (2007), there was no clear
fault scarp at the ground surface. The rupture mechanism released by USGS (2011)
implies that the rupture should cause about 30-60 cm uplift, which may be diluted oversoft deposits. Following the main shock on October 23, about 2000 intensive
aftershocks have also occurred. One of the aftershocks had a moment magnitude (M W )of 5.7 and a local magnitude of 5.8, and the other five were greater than 5. The
earthquake was felt over a large area in the eastern and southeastern parts of Turkey,
including the cities Diyarbakır, Batman, Şırnak, Muş, Erzurum, Bingöl, Bitlis, Ağrı andIğdır.
According to the Turkish Statistical Institute, the provincial population of Van is1.035.418 as of 2010 and the population of Van city center is 539.619. The earthquake
resulted in heavy damage to buildings and significant casualties in this province,
particularly in Erciş town, which is far from the epicenter approximately equal to the
distance between Van and the epicenter, Van city center and number of villages in theprovince. According to the official report released by the Disaster and Emergency
Management Presidency (AFAD, 2011), the casualties are 604 and the number of
injured people is more than 4000, which were caused by collapsed or damaged

1

residential and commercial buildings. A number of buildings collapsed particularly inErciş town (about 60 buildings) and Van (one building). Preliminary damaged survey
carried out by AFAD as of October 28, 2011 indicates that damaged-uninhabitablebuildings and households are 5739 and 8026, and damaged-habitable buildings andhouseholds are 4882 and 7660, respectively. The estimated economic loss has not beenclarified yet.
BLACK SEAMEDITERRANEAN
SEA

Figure 1.1. Location of the Van province (shown by red arrow) in Turkey.

Most of the buildings in Van and partly in Erciş are typically multi-story
commercial/residential reinforced concrete structures. A large percentage of thecollapsed or severely damaged buildings in these settlements were generally in 5-7 story
range. The minarets of many mosques and chimneys of buildings were toppled andadobe buildings commonly built in villages collapsed and/or heavily damaged. There
was also some damage to highway bridges. The highway connecting Van to Erciş town
and to the city of Ağrı was also slightly deformed at a certain location crossed by theearthquake fault. However, on the contrary to the surface rupture of the 1999 Kocaeli
earthquake of Turkey, since the earthquake faulting didn’t result in a continuous andclear rupture on the near surface, except a few concrete canal linings and asphalt
pavements at limited locations, no damage to structures due to surface rupture has
occurred.

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Figure 1.2. Map showing the sites visited during the reconnaissance study by the authors after
the Van-Erciş earthquake, and the epicenters of the October 23, 2011 (M w =7.2) and November
9, 2011 (M L =5.6) earthquakes.

3

In this earthquake, liquefaction and associated ground deformations were evident andwidespread sand boils were observed particularly in Erciş Plain and the flood plain ofKarasu River at the north of Van city. In addition to poor quality construction andinappropriate construction materials, the damage was caused partly by the permanent
displacement of ground by the liquefaction and liquefaction-induced lateral spread of
the ground, at the northern part of the earthquake-affected region, in the vicinity ofErciş town.
One of the typical effects of this earthquake is a change in the shoreline of Van Lake.
The measurements at certain locations on the lake shore at the northern and easternparts of the earthquake region indicated that uplift of the recent shoreline ranging
between 15 and 35 cm has occurred. This is due to the movement of the hanging-wallof the thrust fault causing the earthquake. The distances from the earthquake epicenter
to Van and Erciş were approximately same. However, the damage was quite heavy inErciş as it was on the hanging-wall side of the causative fault while the damage in Vancity was relatively less as it was on the footwall side of the causative fault. Therefore,
in this report, this earthquake is called “Van-Erciş Earthquake of October 23, 2011”.
17 days after the Van-Erciş earthquake, the region was also hit by another earthquakewith a magnitude of 5.6 (M w ) on November 9, 2011 at 19:23 on local time. The
epicenter of this earthquake is located near Edremit which is a town on the eastern shore
of Lake Van about 16 km to the south of Van city center (Figure 1.2) and theearthquake is called Van-Edremit earthquake of November 9, 2011. The moment tensor
solutions of USGS (2011) and GFZ (2011) indicated that the causative fault of thisearthquake was a strike-slip fault. The focal depth of the earthquake estimated by
KOERI (2011), EMSC (2011) and USGS (2011) is between 5 and 6 km. However, it is21.5 and 23 km according to the Earthquake Department of AFAD (ERD; 2011) andGFZ (2011), respectively. This earthquake caused the collapse of 25 buildings in Vancity center. Fortunately, 23 of the collapsed buildings had been evacuated due toprevious damage occurred in October 23, 2011 earthquake. However, two hotel
buildings were open during this second earthquake and some of the people staying there4lost their lives. The total dead loss and injured people caused by this earthquake are 40
and 30, respectively. This earthquake also caused additional damage to some buildings.
This report outlines the investigation undertaken between November 3 and 5, 2011 by areconnaissance team consisting of four investigators, who are the members of JapaneseSociety of Civil Engineers (JSCE), on various aspects of the Van-Erciş earthquake ofOctober 23, 2011 occurred in the Van province. In the first half of the report, geology,hydrogeology, tectonics and seismo-tectonics of the Van province are outlined from ageneral point of view. The second half involves seismic characteristics of theearthquake and faulting, assessments of strong ground motion characteristics, local site
conditions and damage to various types of structures, transportation and industrial
facilities and lifelines, and geotechnical damages in conjunction with site observations,
measurements and computations performed by the authors and evaluation of soil
characteristics obtained from various sources. Finally evaluation of the findings fromthese investigations and lessons learned from this earthquake are concluded. In addition,
based on the information gathered from different sources and the tests carried out someliquefied soils, the general characteristics of the November 9, 2011 Van-Edremit
earthquake and associated damages are also briefly introduced. The sites visited by theauthors during the reconnaissance study are also shown in Figure 1.2.

5

2. GEOLOGY AND HYDROGEOLOGICAL CHARACTERISTICS OF THE
EARTHQUAKE AFFECTED AREA

2.1. Geology

The Van Lake Basin is located at the East Anatolian Plateau which is resulted from thecollision between the Eurasian and Arabian Plates in Late Miocene (Şengör and Kidd, 1979;Şengör and Yılmaz, 1981). The basin, formed in Late Pliocene (Şaroğlu and Yılmaz, 1986),
is underline by a basement consisting of Bitlis Metamorphics, Upper Cretaceous ophiolites
and Tertiary aged marine sediments.

In the Van Lake region surrounding Van Lake,different rock units and alluvial deposits formed between Paleozoic and Holocene areobserved. As seen from the simplified geological map given in Figure 2.1, the Van Lakeregion includes metamorphic rocks belonging to the Bitlis Massif at the south, volcanic andvolcano-clastic rocks at the west and north originated from the old volcanoes called Nemrut
Süphan and Tendürek, volcanic and ophiolitic rocks of the Yüksekova Complex at the east,and young-recent fluviatil and lacustrine deposits.
Based on the generalized stratigraphical column of the region, the oldest units are
represented by the Bitlis Massif which mainly consists of rock units of different
metamorphic facieses (mainly schist, gneiss, marble and quartzite) and ophiolites belonging
to old ocean floor (Yılmaz et al., 1981) (Figures 2.2 and 2.3). The age of these rocks are
considered as Pre-Permian. The Upper Cretaceous ophiolitic melange of the Yüksekova
Complex (Yılmaz et al., 1993; Parlak et al., 2000) is mainly composed of serpentinite,
radiolarite, gabro and limestone blocks. Although it is not shown in Figure 2.2, a flysch
facies of Upper Paleocene, which is composed of detritic rocks, is also considered as thelatest facies of the Yüksekova Complex (Çiftçi et al., 2008). In some areas, these rock units
are overlien by Tertiary formations with an angular unconformity.
The Van formation, cropping out at the south of Van, and west of Erciş and Adilcevaz towns
at the north, mainly consists of alternations of sandstone, mudstone and turbitides including
pebble layers (Figures 2.1 and 2.2).

This formation has thinly-to-moderately spaced

6

beddings and its age is Late Oligocene-Early Miocene (Sağlam, 2003). During thedeposition of the Van formation at the east, thickly bedded and fosillifereous limestones
have also deposited near to Adilcevaz and Erciş at the northern part of the region (Sağlam,2003). However, these limestones, called Adilcevaz limestone, are not separately shown on
the map given in Figure 2.1.

Figure 2.1. Simplified geological map of the close vicinity of Van Lake (modified and from Üner etal., 2010)

The Van Gölü formation, observed at the eastern and northern parts of the region (Figures
2.1 and 2.2), is mainly represented by fluvial deposits consisting of loosely packaged
conglomerates and sandstones, and marl-sandstone-claystone alternations deposited inlacustrine environment. The majority of these deposits have formed depending on thevariations in the water level of Van Lake occurred after the latest ice period (Late7

Pleistocene) (Degens et al., 1978) and they unconformably overlie the old units (Özkaymak,
2003).

Figure 2.2. Generalized and simplified columnar section of the region shown in Figure 2.1. (after
Aksoy, 1988 and Acarlar et al., 1991)

A volcanic activity started in Late Miocene and continued to the recent is a result ofcompressional tectonic regime affecting the region (i.e. Yılmaz, 1990; Aydar et al., 2003;
Keskin, 2005). In this period, the materials ejected from Nemrut, Süphan and Tendürek
volcanoes, became the sources of the volcanic and volcano-clastic rock units covering thenorthern part of the Van Lake region (Figures 2.2 and 2.3). The volcanic units in the vicinityof Nemrut Mountain are in basaltic and rhyolitic character, while the volcanics of theSüphan Mountain are represented by rhyolites and andesites. In addition, these volcanics
include andesites and tuffites. Typical outcrops of the basalts in the earthquake-affected
region are observed at the near east of Erciş town.

8

Figure 2.3. Simplified geological map of the Eastern Anatolia region showing tectonic units,
collision related volcanic products and volcanic centers (E-K-P: the Erzurum-Kars Plateau; NATF
and EATF: North and East Anatolian Transform Faults. Volcanic centers: Ag: Mt. Ağrı (Ararat),
Al1: Mt. Aladağ (SE of Ağrı), Al2: Mt. Aladağ (NW of Horasan), Bi: Mt. Bingöl, Bl: Mt.
Bilicandağı, D: Mt. Dumanlıdağ, E: Mt. Etrusk, H: Mt. Hamadag, K: Mt. Karatepe, Ki: Mt. Kısırdağ,M: Mt. Meydandağ, N: Mt. Nemrut, S: Mt. Süphan, T: Mt. Tendürek, Y: Mt. Yağlıcadağ, Z: Mt.
Ziyaretdağ) (Keskin, 2005).

Quaternary aged travertines are observed in Edremit town at the south of Van (Figure 2.1).
These yellowish-brown travertines, called Edremit travertine (MTA, 2002), are massive andtheir bedding planes are not clearly developed, and although their thickness is not uniform, it
ranges between 50 and 80 m (Kıraner, 1959). It is considered that Edremit travertines haveformed from the waters rich in dissolved carbonates which were associated with the
Pleistocene volcanism (Degens et al., 1978).

9

The Holocene deposits in the region are mainly consist of alluvial fan deposits, lacustrine
and fluviatile deposits and debris material including loosely-to-moderately cemented gravel,sand, silt and unconsolidated clay horizons. Selçuk and Çiftçi (2007) interpreted thesesediments as representing four phases of deposition, such as lacustrine deposits, lacustrinefluviatile deposits, shore sand deposits and recent fluviatile deposits (Figure 2.4). Suddenchanges in their lithologies and thicknesses were also reported by the same investigators.

Figure 2.4. Four phases of deposition for the Holocene deposits in the vicinity of Van interpreted by
Selçuk and Çiftçi (2007).

2.2. General Hydrogeological Characteristics of the Earthquake Region
The earthquake region is under the influence of continental climate marked by long andsnowy winters, and dry and hot summers. Although flooding is not common, heavy rainfalls

10

or a rapid increase in temperature leading to snow melt may cause flooding at the beginningof spring.
Van Lake is situated at 1,648 m asl (above sea level) in the eastern Taurus mountains and thelargest fourth largest terminal lake in the World (a body of water with streams flowing into it
but no streams flowing out). Its surface area is about 3,600 km2 and mean depth is between
200 and 300 m and maximum water depth of the lake was measured as 451 m near
Adilcevaz at north (Selçuk and Çiftçi, 2007; Özler, 2008). Van Lake was formed about
100,000 years ago when the volcano-clastic products of Mt. Nemrut damaged the Murat
River valley around Tatvan (Degens and Kurtman, 1978). The lake water level varies
between 1648 and 1650 m since 1969 and an increase of 2 m in water level was observed
between 1987 and 1997, and then a drop in water level occurred until 2001 (Özler, 2008).
Van Lake has a large drainage area (12,500 km 2) and 101 rivers and streams in different
sizes flow to the lake (Özler, 2008). In this area, there are ten big rivers flowing to the lake
following different routes as seen in Figure 2.5. Among them Karasu River, flowing in NESW direction, is the longest river in the earthquake affected area and formed a large plain at
the north of Van. Similarly, another plain at the northern part of Van Lake has been createdby Zilan Stream in the vicinity of Erciş.
The region affected by the Van-Erciş earthquake of October 23, 2011 covers a very large
area between Van and Erciş settlements. The groundwater table is generally close to theground surface in the cities and towns situated on low lands where damage was quite heavy.
In the following paragraphs, the groundwater conditions in and close vicinities of Van cityand Erciş town were briefly evaluated based on the data obtained from previous studies
performed in the region.

11

Figure 2.5. Boundaries of the Van Lake Basin and main rivers (arranged by Çiftçi et al., 2008 from
Köse et al., 2005).

Based on long-period measurements in 33 borings drilled in the Van Plain, the groundwatertable in Van and its close vicinity has an inclination from east to west and SW depending on
topography, and the depth of static water level in these boreholes ranges between 1 and 29 m
(Figure 2.6) (Özler, 2008). Özvan et al. (2005) also indicate that groundwater table is very
close to the ground surface next to Van Lake (1646 m) and at a depth of 12 m in the city
center. In addition, a study for the microzonation of Plio-Quaternary soils at the Yüzüncü Yıl
University (YYU) campus area, which is located on the shore of Van Lake at the NW of Vancity center (Figure 2.6), was carried out (Selçuk and Çiftçi, 2007). This study based on thedata from 31 boreholes suggested that the depth of the groundwater level in YYU campus

12area was between 1.5 to 10 m with flows to S and SW indicating the presence of a shallowseated groundwater table (Figure 2.7).

Figure 2.6. Hydrogeological map of Van and its vicinity (Özler, 2008)
The Van aquifer is an 11 km wide and 14 km long aquifer with an area of 90 km2. Özler
(2008) mentioned that the Van Gölü formation forms this aquifer in the vicinity of Van andhas shore plain aquifer characteristics. Inclination of the layers in this formation, which ismainly composed of sands and gravels with clay interlayers, is between 15 and 300 towards
Van Lake. This aquifer was separated two sub-aquifers by Özler (2008): (i) upper nonpressurized aquifer with a total thickness of approximately 150 m at the east, and (ii)towards Van Lake it transforms to a pressurized aquifer due to an increase in the thickness of13

the upper clay layer (Figure 2.8). This investigator also reported an artesian (+2 m) in theboreholes drilled at the vicinity of port of Van. From Figure 2.8, it is clear that particularly atsouth, a sandy-gravelly layer with a thickness of 5-10 m is observed at the surface. This
layer shows a pressurized character due to the presence of a clay layer of 2-8 m thickoverlaying it. This clay layer is overlain by the main aquifer composed of sandy-gravelly
layers of 5-50 m thick. This aquifer becomes thicker at northern part when compared to thatin the southern part.

In this aquifer, the variation of the depth of groundwater table withtime (between 2001 and 2002) shown in Figure 2.9 suggests that the groundwater tablereaches up to its maximum level in March and April, and to the lowest level in July andAugust, and the groundwater table does not fall at an elevation below the water level in Lake
Van (Özler, 2008).

Figure 2.7. Hydrogeological map of the Yüzüncü Yıl University campus area (Selçuk and çiftçi,
2007)

14

Figure 2.8. Hydrogeological cross-sections of the Van aquifer based on the data from boreholes andgeophysical investigations (Özler, 2008)

Figure 2.9. Variations in monthly piezometric level of the groundwater in Van aquifer (Özler, 2008)

The most damaged settlement in the earthquake-affected region is Erciş town located at thenorthern side of Van Lake. The main drainage system of the Erciş Plain was formed by Zilan
15

and İrşat streams (Figures 2.5 and 2.10). Discharges of the Zilan and İrşat streams measured
at the locations, where they reach to Van Lake, were 4622 lt/s and 918 lt/s, respectively (DSİ,1977). The aquifer in this area, similar to that in the Van Plain, is represented by PlioQuaternary deposits with a thickness reaching up to 188 m (DSİ, 1977). The measurementsfrom 11 water wells in Erciş by Köy Hizmetleri Bölge Müdürlüğü indicated that depth of
the static water level was between 0 and 12 m, and in some boreholes artesian pressures
were also noted (Figure 2.10) (Özvan et al., 2008). At the outside of the Erciş Plain, thedepth of groundwater table increases and may reach up to 74 m deep. 18 boreholes drilled byÖzvan et al. (2008) in Erciş town for a geotechnical investigation indicated shallow-seatedgroundwater table ranging between 1 and 8 m which confirm the previous information
obtained from water wells in the close vicinity of the town by DSİ (1977). In addition, thegroundwater table map of Erciş Plain, which covers a larger area than the map given in
Figure 10 and prepared by DSİ (1977), is also shown in Figure 2.11. This map clearly
indicates that direction of groundwater flow is towards SE and SW and the depth ofgroundwater table becomes considerably shallower near to the lake.

Figure 2.10. Groundwater depth contour map of Erciş town (Özvan et al., 2008)16

From the groundwater level measurements taken from a number of boreholes drilled in Van
and Erciş plains, it can be concluded that the water table is generally close to the groundsurface and depth of the static level from the surface ranges between 1 m and 12 m. But nopublished and/or reported information on hydrogeological characteristics of the areas
particularly those between Van and Erciş (Karasu Plain at the north of Van and west ofErciş) are available. However, wide spread liquefaction occurred during the Van-Erciş
earthquake of 2011 and a number of main streams and their sub-branches flowing are themain indicators of the presence of shallow-seated groundwater table in these areas.

Figure 2.11. Groundwater contour map of the Erciş Plain (after DSİ, 1977)

17

3. NEOTECTONICS OF THE EAST ANATOLIAN REGION AND MAJOR ACTIVE
FAULTS IN THE EARTHQUAKE-AFFECTED AREA

3.1. General Neotectonics of the East Anatolian Region
The Van Lake Basin is located at the northern front of the Bitlis Suture Zone (BSZ) formed
predominantly as a result of neotectonic activity. It is bounded by the Kargapazarı junction
between the North Anatolian Fault (NAF) and East Anatolian Fault (EAF) to the west andZagros fault zone to the east (Figure 3.1). The northern branch of Neo-Tethys was closed by
final collision and suturing of Eurasia in the north and the Anatolian-Iranian platform in thesouth (i.e. Adamia et al., 1981; Koçyiğit, 1991). But the Bitlis Ocean, which is the southernbranch of Neo-Tethys, persisted by the late Middle Miocene (Serravalian) and then closed
entirely by the continent-continent collision of the Arabian and Eurasian plates (Şengör andYılmaz, 1981; Dewey et al., 1986) (Figure 3.1). Geological studies carried out in the region(i.e. Şengör and Kidd, 1979; Dewey et al., 1986 Şaroğlu and Yılmaz, 1986) suggest that theneotectonic activity in Eastern Anatolia dates from the Serravalian (10-14 Ma ago). The
intra-continental convergence and N-S directed compressional tectonic regime remained at
the end of Late Miocene and late Early Pliocene, in place along the BSZ (Koçyiğit et al.,2001). The N-S trending compression regime resulted from the collision of the Arabian andAnatolian plates and the break-off of the subducting front of the Arabian plate, which
resulted in formation of extensive high plateau with an average elevation of 2 km asl., gave
rise to the development of extensions and strike-slip fault systems in front of the BSZ(Keskin, 2005). The strike-slip faults are also observed at the eastern part of Van Lake that
was affected by the October 23, 2011 earthquake. Koçyiğit et al. (2001) also indicate E-W
trending, north-to-south vergent thrust faults and E-W trending folds (Figure 3.2). Volcanic
activity initiated immediately after the rapid block uplift of Eastern Anatolia and became
widespread all over the region, producing subaerial lava flows and pyroclastic products
which are very variable in their composition and eruptive style (Pearce et al., 1990; Keskin
et al., 1998; Yılmaz et al., 1998). In Early Pliocene, three major neotectonic structures,dextral North Anatolian (NAF) and sinistral East Anatolian (EAF) transform faults and thenthe Anatolian plate, which commenced to escape in WSW direction onto the oceanic

18lithosphere of the African plate due to the higher relative movement and anticlock-wiserotation of the Arabian plate developed (Hempton, 1987; Koçyiğit and Beyhan, 1998; Aydan,
1997).

Figure 3.1. Main tectonic features of Turkey and surroundings (after Gülen et al., 2002).

The East Anatolian plateau, where the Van Lake Basin also takes place, and its boundary
zones are the major structures of the Alpine-Himalayan convergent system. The intracontinental convergence, that is much more severe within and nearby the suture, is still
continuing throughout these structures in NNW-SSE direction. It resulted in a series of E–W
trending compressional features such as the WNW-trending thrust faults, folds and ramp
basins with the reverse fault-bounded margins in the east Anatolian plateau during the
Miocene time. The volcanism also accompanied the development of these compressionalfeatures during the Late Miocene–Early Pliocene transitional period that separates the preSerravalian palaeotectonic period from the Late Miocene–Early Pliocene transitional period

19that separates the pre-Serravalian palaeotectonic period from the Plio-Quaternary
neotectonic period (Koçyiğit, et al., 2001).

Figure 3.2. Seismotectonic map of the Van Lake Basin and its surroundings (modified from Koçyiğit
et al., 2001 and Koçyiğit, 2002; KOERI, 2011)

3.2. Major Active Faults in the Earthquake Affected Area
The area affected by the 23 October and 9 November, 2011 earthquakes, is located in thetectonically controlled the Van Lake Basin. By considering the closeness of some faults inthe earthquake region, brief descriptions of some major faults are given in the following
paragraphs. From north to south, these faults are Çaldıran fault, Karayazı-Erciş fault zone,Özalp fault, Gürpınar fault, Gevaş fault and Bahçesaray fault. Although some of these faults
are not shown on the active fault map of Turkey (Figure 3.3), they are all given in Figure 3.2.

20

Figure 3.3. Active faults in the Van Lake Basin and its surroundings shown on the active fault map ofTurkey (after Şaroğlu et al., 1992)

The Çaldıran fault trending in NW-SE and 60 km long is located 40 km NE of Van Lake
(Figures 3.2 and 3.3). It is an active dextral strike-slip fault of 55 km long which caused the1976 Çaldıran earthquake with a local magnitude of 7.2 (M b : 6.9; M s :7.3) (Toksöz et al.
1977). 0.5-1 km horizontal off-set stream channels (Deli and Bendimahi rivers), deep-

21

narrow and long fault valleys developed across the Bemraz and Kösedağ volcanoes, andpressure ridges and pull-apart basins resulted from both its right step-over and bifurcation
are the strong morphological evidences of its recent activity (Koçyiğit et al., 2001).
The Karayazı-Erciş fault zone, approximately parallel to the Çaldıran fault, is a dextral
strike-slip fault located in the central part of the East Anatolian plateau (Figures 3.2 and 3.3).
The northern block of the fault is 80 m morphologically higher than its southern block andconsists of older rocks with respect to the southern block. Moreover along the western partof the fault, the reverse faults of Late Miocene age and some streams (Elmalı and Karasu
Rivers) are cut and offset in dextral direction 3 km and 1 km, respectively, by the fault
implying that the fault is younger than Miocene (Koçyiğit, 1985).
The Özalp fault is a left lateral strike-slip fault trending in approximately E-W betweenÖzalp town and Lake Van (Figure 3.2). Its length is about 60 km and it reaches Van Lake
about 10 km north of the campus of 100. Yıl University and can not be followed under thelake (Selçuk and Çiftçi, 2007).
The Gevaş fault is a right lateral strike-slip fault. It is located at the south of Van Lake andlies between Gevaş and Gürpınar towns (Figures 3.2 and 3.3). Its trace can be followed on
the ground as much as 30 km (Selçuk and Çiftçi, 2007). The Gürpınar and Bahçesaray faults,
approximately trending in E-W, are the other young fault systems in the region. Both faults
have strike-slip characteristics (Figures 3.2 and 3.3).
In addition, Ketin (1977) distinguished four separate fault zones on the basis of his
observations made in the region between Van Lake and Iranian border following the 1966
Varto and 1976 Çaldıran earthquakes and indicated that they could be active faults. Thesefaults, trending approximately E-W (N75-85W) (Figure 3.4), were distinguished based on
their morphological features and some evidences observed at some certain locations.

The

second part of Fault-I in Figure 3.4 starts from the northern tip of Van Lake and continues tothe Iranian border. Based on the observations in streambeds, Ketin (1977) described that thisfault is a right lateral strike-slip fault. Fault-II, starting from the shore of Van Lake, crossing22Lake Erçek and reaching to the Iranian border, indicated that the horizontal movements havealso right lateral strike–slip characteristics. Fault-III, which closely locates to Van city center,
was also classified by Ketin (1977) as a right lateral strike-slip fault based on the evident
fault striations he observed. The last fault zone (Fault-IV) is located between Gevaş and
Gürpınar towns and consists of E-W trending segments. Ketin (1977) also reported thattravertine occurrences were observed along the fault zone. However, Ketin (1977) indicatesthat these faults should be considered as probable faults and further studies on these faults
are needed.

Figure 3.4. Principal fault zones of the eastern and northern parts of the region of Van Lake and thecausative fault of the Çaldıran earthquake of November 24, 1970 (Ketin, 1977).

Most recent studies (Özkaymak, 2003; Özkaymak et al., 2004), which aimed to assess fieldobservations of recent faulting in the eastern part of Van Lake, near the Van city, and tocombine them with seismic data to discuss on the seismotectonic characteristics of the region,
indicated the presence of some unknown faults. One of them is a thrust fault observed near
the campus area of Yüzüncü Yıl University located at the NW of the Van city center. Thisfault shown in Figure 3.5 is a thrust fault trending N70E and dipping 45NW. It is observed
to cut across the recent lacustrine deposits of Van Lake. The fault offset changes from about
90 cm in the older deposits to about 20 cm in the youngest sediments immediately below the23

soil horizon, suggesting that the fault surface was reactivated several times. In addition, athrust fault trending in ENE-WSW and located at the north of Aşıt village was mapped(Figure 3.5). Although this fault doesn’t continue to the lake shore (towards Bardakçı village
where the evidents of the surface rupture of the Van-Erciş earthquake of 2011 wereobserved), its trend and type show a general agreement with those of the causative fault of
the 23 October 2011 Van-Erciş earthquake which is discussed in Chapter 5 of the report. At
different places of this area, the recent clastic units have been affected by N-S, NNW-SSE
and NNE-SSW trending normal faults with offsets up to 1 m and minor thrust faults withcentimetric offsets (Figure 3.5). In addition, the above-mentioned investigators reported thatthe shoreline between Van Lake and the Edremit travertines is a sinistral transtensional fault
zone trending NE-SW and other NW-SE trending probable faults in this area may haveaccommodated dextral crustal displacements.

Another most recent map, prepared by

Koçyiğit et al. (2011), also shows the faults in the earthquake-affected region (Figure 3.6). In
Figure 3.6, the Everek fault having thrust fault characteristics and located between Van Lakeand Erçek Lake shows a general agreement with the causative thrust fault of the Van-Erciş
earthquake of 23 October 2011.

24

Figure 3.5 Simplified geological map also showing the faults in the close vicinity of Van (afterÖzkaymak et al., 2004) (Red and blue arrows show the thrust fault near the 100. Yıl Universtiy
campus and the thrust fault having a general agreement with that of the causative fault of the 2011
Van-Erciş earthquake, respectively).

25

Figure 3.6. Most recent fault map of the area affected by the Van earthquakes of 2011(arranged from Koçyiğit et al., 2011).
26

4. SEISMICITY OF VAN LAKE REGION
The tectonics of the region is influenced by the northward moving and subducting the Arabianplate beneath the Anadolu plate. The Anadolu plate squeezed between the the Arabian plate in
the south and the Euro-Asian plate in the north. As a result of these crustal movements, there
are EW trending thrust faults and major fold axis and NW-SE and NE-SW trending strike-slip
faults. The Van Lake Basin is located at the northern front of Bitlis Sture Zone (BZF) formed
as a result of neotectonic activity. Due to this ongoing tectonic activity in the region, strong
earthquakes shook Van Lake Region from time to time. The seismicity of the region based on
historical and instrumental periods are briefly given below.

4.1. Historical earthquakes
Historical earthquakes having different intensities occurred in the Van Lake Region were
picked up from the cataloges compiled by Ergin et al. (1967), Soysal et al. (1981), Eyidoğan
et al. (1991) and Uluçam (2000) are tabulated in Table 5.1 and the locations of theirepeicentres are shown in Figure 5.1.
Ergin et al. (1967) report a devastating earthquake (I=IX) near Van city occurred in 1111,
while the same event dated as 1110 by Soysal et al. (1981). It should be noted that the dates
assigned to some events differ by one or two years depending upon the catalogues. In 1245
and 1246, earthquakes with intensities of VII and VI occurred and affected Ahlat, Bitlis, Muşand Erciş, respectively (Ergin, et al., 1967; Calvi, 1941; Uluçam, 2000). The 1276 earthquake
caused heavy damage in Ahlat, Erciş and Van which was dated as 1275 by Uluçam (2000),
according to Ergin et al. (1967) and Calvi (1941). It was reported that the 1439 and 1441
earthquakes were caused by the activity of Nemrut Volcano and resulted in some heavy
damage and high casualties. In 1646 or 1647, a very strong earthquake (I=IX) caused heavy
damage in Van, Tebriz, Bitlis and Muş. Another earthquake occurred (I=VIII) in the HoşapVan region in 1648 (Ergin et al., 1967; Soysal et al., 1981). It seems that several large
earthquakes occur once the seismic activity starts and continues for several years. Anotherseismic activity up to an intensity of VIII occurred during 1701 and 1705 (Ergin et al., 1967;
Soysal et al., 1981). Erciş experienced an earthquake with an intensity VII in 1715. The Van
region was shaken by an earthquake with an intenisty of

27

VIII in 1871. A very large

earthquake with an intensity of IX-X occurred in the region and affected Van, Bitlis, Muş and
Nemrut area in 1881 (Ergin et al., 1967; Soysal et al., 1981).
Table 4.1. Historical earthquakes occurred in the Lake Van Region.
Çizelge 4.1. Van Gölü havzasında meydana gelen tarihsel depremler
Date (AD)N

E

Affected region

Source43.4

Intensity
(I)
IX

38.5

4

1110 or1101
1245 or1246
1275 or
1276
1439

Van

Ergin et al. (1967)

38.7

43.3

VII

38.8

42.5

VII-VIII

Ahlat, Van,
Bitlis, MuşAhlat, Van, Erciş

38.6

42.3

VI

Ergin, et al. (1967);
Calvi (1941)
Ergin, et al. (1967);
Calvi (1941)
Ergin et al. (1967);
Soysal et al. (1981)

5

1582
1441

38.7
38.3
5

41.5
42.1

VIII
VIII-X

6

1647

39

44

IX

7

1648

38.3

43.5

VIII

8

1701

38.5

43.4

VIII

Hoşap-Van,
Muş, TebrizVan91704 or1705
10 1715

38.5

43.4

VI-VII

Van

43,6
5
43

IX

Van-Erciş

11 1871

38.9
5
38

VII

Near Van

12 1881

38.5

43.3

IX, X

13 1900

38.4
7

43.3

VI

Van, Bitlis, Muş,Nemrut area
Van

N
o
1
2
3

Nemrut area due
to volcanic
eruption
BitlisBitlis, Muş,Nemrut area,
Ahlat, Erciş, Van
BitlisSoysal et al. (1981)
Ergin et al. (1967);Öcal (1968); Soysal etal. (1981)
Ergin et al. (1967);
Soysal et al. (1981)
Soysal et al. (1981)
Ergin et al. (1967);
Soysal et al. (1981)
Ergin et al. (1967);
Soysal et al. (1981)
Ergin et al, (1967);
Soysal, et al, (1981);
Ergin et al, (1967);
Soysal et al. (1981)
Ergin et al, (1967);
Soysal et al. (1981)
Ergin et al. (1967)

4.2. Earthquakes occurred in the instrumental period (1900-2011)
In addition to the catalogue published by Ergin et al. (1967), Eyidoğan et al. (1989) compiled
a catalogue for the earthquakes occurred between 1900 and 1988, there are two major periodsof earthquake activity between 1900 and1904, and 1941and 1945, respectively. The seismic
activity initiated at Erciş with an intensity of VIII (M s 5.9) in 1941 and, followed by several
shocks lasted until 1945. In this period, the 1903 Malazgirt (M=6.3), 1930 Salmas (Iran)28

(M=7.2), 1941 Erciş (M=5.9) and the 1945 serial earthquakes affecting the Van Region (thebiggest one M=5.2) are the major earthquakes. The other major earthquakes in the close
vicinity of Van Lake are 1966 Varto (M s 6.8), 1975 Lice (M s 6.6) and 1976 Çaldıran (M s 7.3)
earthquakes. The Varto and Lice earthquakes are of thrust type. While the Çaldıran (M s 7.3)
earthquake has a right lateral strike-slip character and the maximum displacements along thefault reached to 4 m close to the eastern end of the rupture, whereas the average slip was inorder of 2 m. The 1976 Çaldıran (M s 7.3) earthquake also induced some discussion on thecontinuity of the North Anadolu Fault Zone (NAFZ) to the east of Van Lake extending
towards Iran. The çaldıran earthquake produced a 55 km long zone of surface rupture (Toksöz
et al. 1977: Arpat et al. 1977). This earthquake caused 3840 fatalities demolishing about
10000 buildings. Arpat et al. (1977) and Ketin and Abdüsselamoğlu (1977) reported that thenorthern shore of Van Lake was uplifted for about 12-16 cm as a result of Çaldıranearthquake. Two moderate scaled earthquakes having moment magnitudes of 5.4 on June 14,
1988 and 5.7 on November 15, 2000 recently occurred in the eastern part of Van Lake. The
faulting mechanisms of these earthquakes were all of thrust type.

Figure 4.1. Epicenters of the historical earthquakes occurred in the Van Lake Region.given in
Table 4.1.
The focal plane solution of the earthquake occurred in the vicinity of Edremit town, at theSouth of Van, on December 2, 2001 indicated a thrust fault and its strike was very similar to29those of the thrust faults observed in the region (Özkaymak et al., 2004). Although thisearthquake with a focal depth of 18 km didn’t cause any loss of life, some cracks occurred on
the walls of some buildings situated on loose sediments. Figure 4.2 shows that earthquake(M>4) activity of the region between 1900 and 2011.

Figure 4.2. Seismicity of the Van Lake Region between 1900 and 2011 based on theearthquakes with magnitudes greater than 4 (Base map from MTA, 1998; arranged from
Sayısal Grafik, 2011).

30

5

SEISMIC CHARACTERISTICS OF THE VAN-ERCİŞ EARTHQUAKE AND
FAULTING

5.1. Earthquake Focal Mechanism and Faulting

The main shock occurred at 13:41 (10:41GMT) on Turkish standard time on October 23,
2011 in the Van province of Turkey. Various institutes in Turkey and other countries
determined the epicenter of the earthquake and its faulting mechanism as shown in
Figure 5.1. As noted from Figure 5.1 the locations of the epicenters predicted by various
institutes such as KOERI, USGS, ERD, HARVARD and GFZ are scattered. Kandilli
Observatory and Earthquake Research Institute (KOERI, 2011) estimated that theearthquake was centered about 30 km north of the Van city center near Tabanlı village.

The major energy release occurred within 20 seconds although the total duration of the
rupture was about 50 seconds. KOERI estimated that the epicenter of the earthquake
was near Tabanlı village (38.628N, 43.486E). The earthquake resulted from the
movement of a 50 km long and 20 km wide thrust fault trending about E-W direction
from Erçek Lake into Van Lake.

The rupture mechanisms released by different institutes (USGS, 2011; HARVARD,
2011; KOERI, 2011; ERD, 2011; GFZ, 2011) implied that the rupture was due to thrust
type faulting as seen from Figure 5.1 and Table 5.1. The focal mechanism inferred fromthe striation of a fault observed in Topraktaş village based on the fault striation method
developed by Aydan (2000) is also given in Figure 5.1. In view of the seismicity, theNW dipping faults may be assumed to be the causative fault with a slight sinistral31

component. The average inclination of this NW dipping fault may be about 40-60
degrees. Although the estimated average relative displacement of the fault is more than
2 m according to the empirical relation proposed by Aydan (2007), there was no clear
fault scarp on the ground surface.

Regarding the active fault map of Turkey prepared by Şaroğlu et al. (1992), it wasinteresting to note that no active fault is recognized in the epicentral area. A moredetailed tectonic map of the epicentral area has been released by Koçyiğit et al. (2011)
following the earthquake as shown in Figure 5.1. They also attempted to relate the faults
drawn in this map with the focal mechanism solutions of main and major aftershocks.
However, this attempt is quite disputable in many aspects.

Table 5.1.

Seismic parameters of the Van-Erciş earthquake of October 23, 2011 by USGS

(2011), HARVARD (2011), ERD (2011), GFZ (2011) and KOERI (2011).

Institute

Lat.

Lon.

Depth

(N)

(E)

(km)

GFZ

38.9

43.8

19

HARVARD

38.67

43.42

15

ERD

38.69

43.47

19

USGS

38.69

43.50

16

KOERI

38.76

43.36

5

ML

Ms

6.7
7.1
6.6

Mw

NP1

NP2

StrikeDip

Slip

Strike

Dip

Slip

7.1

254

56

74

101

38

112

7.1

248

36

60

104

60

110

7.0

283

24

95

98

66

88

7.1

241

51

58

106

49

123

7.2

292

61

125

32

Figure 5.1. Faults mapped by Koçyiğit et al. (2011) and focal mechanism solutions by various
institutes (Focal mechanism solution using the data measured in Topraktaş is derived from themethod of Aydan, 2000).

5.2. Aftershock Activity
Figure 5.2 shows the locations of aftershocks following the October 23, 2011
earthquake just before the November 9, 2011 Van-Edremit earthquake. The aftershocks
distributed over an area, which is about 50 km long and 20 km wide. This area extends
from Erçek Lake into Van Lake. In the same Figure, projected seismicity with depth
along NS and EW directions is also shown. It is also interesting to note that somepre-seismic activity is observed in the vicinity of the epicenter of November 9, 2011
earthquake.

33

Figure 5.2.

Aftershock activity following the main shock (aftershock data from ERD).

As noted from seismicity projected on “NS-depth” space, two distinct fault planes
denoted by FP1 and FP2 can be inferred. The inclinations of inferred faults FP1 and FP2
are approximately 60 and 40 degrees, respectively. It seems that wedge-like body isundergoing a high seismicity.

5.3. Changes in the Shore Line of Van LakeAs the focal mechanism of the earthquake implies thrust faulting, it may be said that the
body bounded by two planes may be undergoing uplifting. This uplifting also involves
the Erçek Lake. The authors and Emre et al. (2011) noted that the shoreline of Van Lake34

was uplifted by 30-40 cm and it is in accordance with the inference of the seismicity(Figure 5.3). This uplift observed along the northern part of the causative fault, i.e. on
the hanging wall block. Based on the measurements by the authors on the coast of thelake in Erciş town, the land uplifted about 30-33 cm. The authors also measured a
withdrawal of about 45 cm on the lake shore near to Amik Castle and Yeşilsu villas andslight uplift along the shore line between Dağönü and Mollakasım villages. All theselocations are shown by red stars in Figure 5.3. Emre et al. (2011) observed uplifts at ten
locations on the shore of Van Lake between Adilcevaz at the NW and north of Van atsoutheast. These uplifts range between 10 and 40 cm and their locations are shown bypurple stars in Figure 5.3.

Figure 5.3. Views of uplift of the shoreline at several localities along the shore of Van Lake
(Smaller purple and big red stars are the observations of uplifting reported by Emre et al., 2011and by the authors of this report, respectively).

35

5.4. Surface Ruptures
Following the earthquake, many reconnaissance teams were dispatched to the epicentral
area. The team dispatched by MTA (Emre et al., 2011) found traces of surface ruptures
and they produced a fault trace map from Erçek Lake into Van Lake as shown in Figure
5.4a. The surface rupture could be traced from Bardakçı village located on the east
shore of Van Lake at the north of Van towards east about 4 km (Akyüz et al., 2011).

Although there was no clear well-defined fault scarp along the fault trace, some uplift ofground, roadways, compression of bridges, canals slope failure and extensiveliquefaction and associated lateral spreading over the fault front. The three locations,where the authors have observed the traces of the surface rupture, are also shown in
Figure 5.4. One of them is located at east of the road between Bardakçı and Topaktaş
villages (NW of Zeve Akademi Houses). At this location, a displacement about 5-6 cm
was measured in a concrete water canal oriented perpendicularly to the surface rupture
and it was observed that the part of the canal on northern block trusted towards south(Figure 5.4b). At the second location, a deformation trending in N50E was observed on
the asphalt pavement of the Bardakçı-Topraktaş village and an uplift of 6 cm wasmeasured on the northern block (Figure 5.4c). The deformation of Van-Ağrı Highway
in the close vicinity of Yüzüncü Yıl University Campus at about 7 km north of Van City
also implied slight sinistral lateral movement of the fault and this part of the highway
was repaired (Figure 5.4d). Akyüz et al. (2011), who extended their reconnaissancetowards east, reported that they observed very thin cracks trending N75E on a stabilized
road close to Aşit village and the terraces trending in E-W direction at the south ofGedelova (near west of Erçek Lake) should be possible trace of the thrust fault causing36

the earthquake. According to Emre et al. (2011), the length of the fault on the land is 27
km and it consists of a single segment of 12 km long at its western tip, and twosegments parallel to each other with a total length of 17 km in the east.

Figure 5.4. (a) Map showing the surface rupture of the October 23, 2011 earthquake (Emre et al.,2011), (b-d) locations of the surface rupture observed by the authors, (e) a model showing thedeformation caused by thrust faulting by Ohta and Aydan (2004).

37

As there was no well-defined fault scarp, some researchers claimed that the earthquake
was caused by a blind thrust faulting. When ground near surface is quite soft, thedeformation caused by thrust faulting would be diluted over a great area as seen in the
picture (Figure 5.4e) of a model faulting experiment performed by Ohta and Aydan(2007).
5.5. Comparisons with Other Turkish and Worldwide Earthquakes
Aydan (Aydan et al. 1996; Aydan 1997) developed some empirical relations among
surface wave magnitude (M s ) and various fundamental parameters of earthquakes. He
did not differentiate the fault type in his original relations. After about 10 years later, herevised his empirical relations and replaced the surface wave magnitude with moment
magnitude of earthquakes as it has become quite rare that many seismological institutes
report surface wave magnitude of earthquakes. The fundamental characteristics (i.e.
displacement, length, area and duration) of this earthquake have been compared with
empirical relations of Aydan (1997) and Aydan (2007). In converting M s into M w, therelation established by Aydan (2007) has been used for comparisons. The results areshown in Figure 5.5 with the consideration of fault type for Aydan’s empirical relations
published in 2007. The fault displacement is inferred from INSAR, and fault length andarea were determined from seismic activity for about 10 days following the earthquake.
The duration data comes from the data released by HARVARD (2011). As noted from
Figure 5.5, the data of this earthquake (shown by a red star) is clearly on the estimatedlines from the relations of Aydan (2007).

38

Figure 5.5. Comparison of fundamental parameters of the 2011 Van-Erciş earthquake with
empirical relations proposed by Aydan (1997 and 2007).

39

6. STRONG MOTION CHARACTERISTICS
In the epicentral area, there are a number of strong motion stations operated by thenational strong motion network of Turkey (Figure 6.1). Unfortunately, no strong motion
was recorded in Van and Erciş, although Van and Erciş are equipped with strong motion
devices. It seems that it did not record any strong motion data due to a technicalmalfunctioning.

Figure 6.1. Locations of the strong motion stations in the vicinity of the earthquake epicenter(Black coloured stations have no records due to malfunctioning while yellow coloured stations
have recordings).

6.1. Estimated and Measured Ground Motions and Their Attenuation
The nearest strong motion station to the epicenter of the main shock was located in40Muradiye (38.99011N-43.76302E) and the maximum ground acceleration at this station
with a weighted shear velocity of 293 m/s was about 0.2 g (ERD, 2011). The distance ofMuradiye station to the epicenter is almost the same as that of Erciş. Figure 6.2 shows
the acceleration records taken at Muradiye and Bitlis (38.46600N-42.15000E). The N-Scomponent of Muradiye station is the highest component, which probably reflects
strong directivity effect.

Figure 6.2. Acceleration records taken at Muradiye and Bitlis strong motion stations.

Figure 6.3 shows the acceleration records at Malazgirt and Muş strong motion stations.
The shear wave velocity of ground at these stations is about 300 m/s. The
accelerometers of Muradiye and Malazgirt stations are SMACH type while those at41

Bitlis and Muş are CMG-5TD type. Therefore, some slight differences are notedparticularly in the acceleration records of Malazgirt station.

Figure 6.3. Acceleration records taken at Malazgirt and Muş strong motion stations.
The estimated contours of maximum ground acceleration and ground velocity using themethod proposed originally by Aydan and Ohta (2006) and slightly modified by Aydan
and Ohta (2011a) to include the effect of length and dip angle of the earthquake fault in
addition to the effect of the fault strike, hangingwall and footwall effects are shown in
Figures 6.4 and 6.5 for a uniform distribution of shear velocity of ground. It should be
noted that the actual ground motions should differ from estimations if shear wave
velocity of ground is different. Furthermore, it should also be noted that this type of42estimations does not include topographic and basin effects yet. In the same observed
maximum ground acceleration and velocity values at Muradiye, Bitlis and Malazgirt
stations are also shown. It can be said that the observations are generally close to
estimations. In addition, we plotted inferred maximum ground motions from toppled
simple structures (see Section 6.4 for details) in the same figure. As there was no strong
motion data in the epicentral area, the inferred ground motions may provide some
information on the likely strong motions. The inferred results implied the maximum
ground acceleration and velocity could be 500 gals and 38 cm/s at least, respectively.

Figure 6.4. Contours of maximum ground acceleration.

Figure 6.6 compares the estimations by several attenuation relations proposed by Aydan(2001), Aydan and Ohta (2006, 2011a) and Ulusay et al. (2004) for maximum groundacceleration and maximum ground velocity with observations. The observed data are43

within the bounds proposed by Aydan (2001) and Aydan and Ohta (2011a).

Figure 6.5. Contours of maximum ground velocity.

Figure 6.6. Comparison of estimations by several attenuation relations with observations.

44

6.2. Spectral Characteristics of Ground Motions
The acceleration spectra of the Muradiye, Bitlis, Malazgirt and Muş strong motion
stations for a mass-proportional damping ratio of 5% are shown in Figure 6.7.
Maximum spectral accelerations are observed for a natural period of 0.3-0.5 seconds for
Muradiye record with a peak around 0.4 second for N-S component. The acceleration
response of Bitlis is quite similar to those of Muradiye records. As for the accelerationof strong motion stations such as Muş, Malazgirt and Bitlis away from the epicenter, theeffect of long period components appear as expected. For example, the collapse ofminarets in Muş and Malazgirt can be explained by long period components for strong
motion records. Furthermore, the acceleration spectra of Muş station, has a distinct peak
between 1.2 and 1.3 s. This may be related to a basin effect.
6.3. Natural Periods of Structures in Turkey
Figure 6.8 shows the natural periods of various structures for the first mode together
with formula provided by the Turkish Seismic Codes (Ministry of Public Works andSettlement of Turkey, 1998). In converting the period of RC towers (water tanks), theheight is divided by a common story height of 3.3 m. In addition, a linear function baseda theoretical model of a simple structure is fitted to the data set. The coefficient of 0.065
seems to be the best fit to the data set. The number of story of many collapsed RC
buildings particularly in Erciş ranges between 5 and 8. In view of natural periods
common to reinforced concrete (RC) structures in Turkey, the acceleration response of 6
story RC buildings should have been must vulnerable to high ground shaking in view of
their natural periods in addition to other structural problems. This result may also
explain why 5–8 story RC buildings collapsed or heavily damaged during this45

earthquake.

Figure 6.7. Acceleration response spectra for a damping ratio of 5% at different strong groundmotion stations.

Figure 6.8. The relation between natural periods of various structures in Turkey.
46

6.4. Permanent Ground Motions from GPS and INSAR
Turkey has recently improved its global positioning system (GPS) network (TurkishCGPS). Following this earthquake, the displacement of the GPS stations were released
as shown in Figure 6.9. The largest displacement was observed at Muradiye station on
the hangingwall side of the fault and it had amplitude of 56 mm. This station moved in
the S20W direction. Başkale GPS station, which is on the footwall side of theearthquake fault, moved in N30W direction with an amplitude of 29 mm. Malazgirt
station moved westward with an amplitude of 13 mm. The measured uplift at manystations is very small and may be related to the resolution problem of the GPS in
vertical direction. In any case, it should be noted that the measured displacement by the
GPS may not correspond to actual crustal deformations due to the possibility of plastic
deformation of ground at surface.

Several INSAR techniques have been also applied to the surface deformation caused by
the October 23, 2011 earthquake. Figure 6.10 shows the fringes of inferred crustal
deformation in the epicentral area processed by Eric Fielding of JPL-Caltech. As notedfrom this figure, there are clear indications of surface deformation particularly at thenorth of Van and the highest deformation is observed near the epicenter. The colour
contours in the direction of the radar line sight (28 degrees from vertical and roughlywest) is 20 cm. However, one of the major problems with this technique is that thesurface deformations caused by liquefaction induced lateral spreading and slope failures
can not be differentiated. This is often the case as observed in previous large-scale
earthquakes such as 2005 Kashmir earthquake (Aydan et al., 2006). Therefore, theprocessed results from INSAR techniques should be interpreted with caution.

47

Figure 6.9. Measured displacements at the GPS stations of the national GPS network of Turkey.
(http:supersites.earthobservatory.org/)

48

Figure 6.10. Inferred fringes of surface deformations from INSAR techniques by
COSMOS-Med (http:supersites.earthobservatory.org/CSK-20111010-1026-20 cm).

6.5.Collapse Directions of Simple Structures and Estimated Strong Motions
Collapse directions and inferences of ground motions from simple structures may also
give some indications of possible strong motions in the epicentral area. As there were nostrong motion records in heavily damaged areas, such inferences may provide someinsights to the strong ground motions in the affected areas. Some available techniques inliterature (i.e. Aydan, 2002; Aydan et al., 2004) may be used. Figures 6.11 and 6.12
show inferred maximum ground acceleration and velocity for the sliding and toppling
modes of failure of some simple structures. The inferred maximum ground accelerations

49

and ground velocity are more than 200 gals and 30 cm/s, respectively in Erciş. Sometypical examples of collapses are shown in Figure 6.13.

Figure 6.11. Maximum ground acceleration for sliding and toppling modes.

Figure 6.12. Maximum ground velocity for sliding and toppling modes.

Collapse directions of buildings, minarets, garden walls and chimneys were measured
by the authors during the reconnaissance in the earthquake affected area (Figure 6.13).
Distribution of collapse directions in the epicentral area is generally concentrated innorth and south directions (Figure 6.14).

50

Figure 6.13. Views of failed, toppled and displaced some structures in the epicentral area51

Figure 6.14. Collapse direction of simples structures and movement direction of slopes andground in the epicentral area52

7. DAMAGE TO STRUCTURES
The distances from the earthquake epicenter to Van and Erciş were approximately thesame. However, the damage was quite heavy in Erciş as it was on the hanging-wall sideof the causative fault while the damage in Van city was relatively less probably because
it was on the footwall side of the causative fault. In this chapter, the characteristics ofthe damages to various structures are explained.

7.1. Mosques and Minarets
Most of the main compounds of mosques in the earthquake-affected region weregenerally intact or suffered very slight damage (Figure 7.1). The damage was generally
concentrated at corners as observed in the previous earthquakes of Turkey (i.e. Aydan etal., 2000a, 2000b). The main compounds of mosques generally have single dome or
multiple semi-spherical domes and they are structurally symmetric. For this reason, themain compounds remain intact during shaking. Furthermore, the domes of mosques are
made of very light materials. The main compounds of the mosques either failed ordamaged when the falling minarets hit them. Such examples were observed in Erciş.

The height of minarets in the region ranges between 10 and 25 m. While recently
constructed minarets are mainly reinforced concrete structures, the minarets of old
mosques are stone masonry. The stones are generally made of sandstone and/or andesite.
Failures of minarets occurred at the junctions where the cross-section configuration of
the structure changes by toppling as seen in Figure 7.1

53Figure 7.1. Views from damage to mosques and their minarets.

7.2. Reinforced Concrete Structures
The earthquake resulted in heavy damage to buildings and significant casualties in thisprovince, particularly in Erciş. A number of 5-8 stories RC buildings collapsed
particularly in Erciş and Van (Figures 7.2 and 7.3). The major causes of the heavy
damage to reinforced concrete buildings were basically similar to the observations inprevious earthquakes such as poor quality of construction materials, lack ofimplementation of design codes, existence of soft-floor (weak-floor), pounding, lack ofductility, poor integrity of RC frame with in-fill walls, poor quality of workmanship andpoor ground conditions (i.e. Aydan et al., 2000a, 2000b). It should be added that site
effects most likely contributed to alteration of frequency characteristics of the groundmotions to adversely affect the buildings.

54

Figure 7.2. Views of collapsed or heavily damaged RC buildings.

Figure 7.3. Views of constructional problems causing the collapse or heavy damage.

55

In recent years, TOKİ, which is a state owned construction company specialized inbuildings, have constructed buildings in Van, Edremit and Erciş. These buildings arelike honeycombs utilizing shear walls as the shear load bearing elements. This
earthquake probably is the major event to test their structural performance during
earthquakes. The story number of TOKİ buildings in Erciş is 5 while it is 8 stories inVan. They are generally built on a firm ground. Although the authors could not inspectthese buildings in detail, the visual inspection indicated that there was almost no
damage to the buildings (Figure 7.4).

Figure 7.4. Views of non-damaged TOKİ buildings.

The authors noticed during their reconnaissance that some buildings were repaired bycosmetic non-structural methods such as re-plastering of cracked beams, columns,
infill-walls and beam column connections, which had disastrous effects in theNovember 9, 2011 earthquake (Figure 7.5). Similar problem was observed in buildings

56

damaged by the 1999 Kocaeli earthquake in Düzce during the 1999 Düzce earthquake(i.e. Aydan et al., 2000a and 2000b).

Figure 7.5. Cosmetic repairs apllied to a damaged RC building in Van on November 5, 2011
after the Van-Erciş earthquake.

This earthquake also damaged some low story reinforced concrete buildings constructedalong the shore of Van Lake as villa houses. The major cause of damage was thepermanent deformation of sloping ground towards the lake. Figure 7.6 shows views ofthese damaged villa-type houses. These examples also indicated the vulnerability ofbuildings to the permanent deformation of foundation ground along the lake shore.

57

Figure 7.6. Damaged low story villa-type buildings constructed on sloping ground along theshore Van Lake.

7.3. Masonry Structures
Buildings in rural areas and villages are of brick masonry or stone masonry type.
Timber houses (hımış in Turkish) are quite rare due to lack of forests in the earthquake
affected area. This earthquake damaged many such buildings as seen in Figure 7.7. In
addition to poor quality construction and inappropriate construction materials, thedamage was caused partly by the settlement and lateral spreading of liquefied ground tobuildings. Figure 7.8 shows some examples of geotechnically induced structural
damage at Çelebibağı village of Erçiş.

58

Figure 7.7. Views of heavily damaged brick masonry buildings.

Figure 7.8 Lateral spreading induced damage to buildings in Çelebibağı village (Erçiş).

When these buildings are constructed with the consideration of having a mat concrete or
firm base, light roof, hatıl (timber or conrete confining beams) at certain intervals, lime
(cement)-based bonding, utilization of saman (straws) in kerpiç (adobe) bricks andplastered walls, the damage was none or slight. Such buildings performed very welleven some permanent ground deformation occurred beneath their foundations as seen in
Figure 7.9. There are some golden rules how to construct masonry buildings inearthquake-prone areas, which are outcomes of experiences gained from thelong-history of seismicity of Turkey. These rules can be summarized as follow:(a) Built on a base-mat concrete or firm base (if ground condition is poor)(b) Roof should be light (toprak dam (earthen roof)) is not desirable)(c) Use hatıls (timber or concrete beam) at each 1 m interval at the top of the wall.

59

(e) Use lime (cement)-based mortar with saman (straws) in kerpiç (adobe) bricks(original idea of fiber-reinforced concrete/shotcrete comes from this concept)(h) Plaster walls in order to prevent water diffusion into kerpiç (adobe) bricks

Figure 7.9. Views of non- or slightly-damaged masonry buildings in several localities.

7.4. Elevated Water Towers and Silos
Elevated water towers are commonly used in when ground is quite flat. There weresome reinforced concrete water tanks in Van. Water towers are RC structures and theirheight generally ranges between 25-30 meters. The towers have 6 columns and they are
symmetric structures. Figure 7.10 shows a water tower belonging to the General60Directorate of Highways (TCK) of Turkey in Van city. No damage was observed at thiswater tower. The visual inspection of water tanks at other localities indicated that there
was no damage. The water in this type of elevated water tanks may act as an active
damper during ground shaking. As noted from Figure 6.8, the natural period of thesestructures are generally long. This may be additional factor why such structures are notaffected by earthquakes in this earthquake as well as in previous earthquakes in Turkey.

Figure 7.10. Non damaged elevated water tank owned by the General Directorate of Highways(TCK) in Van city.

Although some silos observed by the authors were intact and did not suffer any damage(Figure 7.11a), KOERI (2011) reported that many cement and wheat silos, which were61

full at the time of the earthquake, either fully collapsed or were seriously damaged(Figure 7.11b-c). Some of silos ruptured at their base due to bending or insufficientseating width of the supporting concrete.
(a)

(b)

Figure 7.11. (a) Non-damaged silos in Van and (b) collapsed cement silo in the Van Industrial
complex (KOERI, 2011).

7.5. Dams
There are several rock-fill dams up to 65 m high and earth-fill water reservoirs in theepicentral area. These dams are Sarımehmet Dam (4 km from the epicenter), Koçköprü
Dam (39 km from the epicenter) and Bostaniçi Dam. Koçköprü Dam and Sarımehmet
6

Dam are a 75 m high clay core rock fill dam with reservoir capacity of 110x10 m3 and a
62 m high clay core rock fill dam with reservoir capacity of 115x104 m3, respectively.
Based on the reconnaissance reports at dam sites in the earthquake region (DSİ, 2011;Çetin et al., 2011), the earthquake did not cause any damage to the dams, for example,
even the Sarımehmet Dam (Figure 7.12) was very close to the earthquake epicenter.
(a)

62

(b)

Figure 7.12. Views from (a) crest and (b) spillway of the non-damaged Sarımehmet Dam (afterÇetin et al., 2011).

7.6. Pre-cast (Prefabrik) Reinforced Concrete Structures

Structures utilizing pre-reinforced concrete columns and beams are widely used forfactories and large ateliers. The first devastating damage to these structures occurred in
the 1992 Erzincan earthquake and since then, there were very similar type damage tothese structures in almost every earthquake having a magnitude greater than 6 (Aydan
and Kumsar, 1996 ; Aydan et al., 1998; Aydan et al., 2000a, 2000b; Ulusay et al., 2002;
Aydan et al., 2003). It was also observed that such damage could even occur in63earthquakes having a magnitude of 5.3-5.6 as seen in the 2003 Buldan earthquakes(Kumsar et al., 2008). Following the heavy damage to these structures in the 1999
Kocaeli and Düzce earthquakes, the seismic design codes of pre-cast structures havebeen revised. Although the authors could not visit such structures due to the limited
duration of their investigation, the information provided by the reconnaissance teams of
KOERI (2011), METU/ERRC (2011) and Özden et al. (2011) reported severe damage
to those structures in the Van Industrial Complex. Figure 7.13 shows a commonly
observed damaged to an old pre-cast concrete structure. Especially, the damage always
occurs at the connection of the reinforced concrete beam to the short cantilever of thecolumn. The beams are attached to the column with two thin reinforcing bars and thebeams become dislodged during shaking either due to rupture of the column end or
rupture or sliding of bars from their anchorage and they fall on the floor, subsequently.
As seen in Figure 7.14, the total collapse of one part of the precast concrete structure
under construction strongly implies that there is no improvement to their seismic design
despite the revision of the code in practice since 1999. It seems that the old practice still
continues. Figure 7.15 shows the details of the beam-column connection the collapsed
pre-cast reinforced concrete structure shown in Figure 7.14.

64Figure 7.13. A typical damage to a pre-cast reinforced concrete structure in Van Industrial
Complex (from KOERI, 2011).

Figure 7.14. A view of heavily damaged pre-cast reinforced concrete structure in Van Industrial
Complex (from KOERI, 2011).

65

Figure 7.15. The details of poorly constructed beam-column connection of the pre-cast structure
shown in Figure 7.14 (pictures arranged from KOERI (2011)).

7.7.

Damage to Historical Structures

Karakoyunlu Türkmen State governed Azerbaijan and Iraq during a period between
1375 and 1468. Erciş served as the capital of Karakoyunlu Türkmen State and there aremany historical remains from that period in Erciş and Provinces of Van and Bitlis. There
are a number of several mausoleums (Kümbet in Turkish) built for the khans (king)and/or their aristocratic families. They are dodecahedral or cylindrical built on a cubic
base. Two kümbets were damaged by this earthquake. Particularly the Kara Yusuf Pasha
Kümbet (also locally known Zortul), which was built near Çatakdibi village of Erciş
during the period of Cihan Şah, suffered very heavy damage by the earthquake as seenin Figure 7.16.

66

(a) before(b) after

Figure 7.16. Heavily damaged Kara Yusuf Pasha Kümbet (pictures from Erciş Municipality and
TRT-Haber, 2011).

The second kümbet damaged by the earthquake is Kadem Pasha Hatun Kümbet. Thiskümbet is about 1–2 km to the east of Erciş, at the junction of the Erciş–Van and
Patnos–Van roads. It was also built in 1458 for the wife (hatun) of Kadem Pasha during
the period of Cihan Khan (Shah). The damage was due to relative movement among
blocks, which caused the opening of vertical joints between stone blocks of the structure
as seen in Figure 7.17.

It was also reported that some stone monuments with cuneiform (originally developedby Sumers, who are of Central Asian origin) inscriptions of Urartu (probably related to
Ural-Altaic origin) period in the Van Museum toppled as seen in Figure 7.18. The
museum building also suffered some damage, some clay tablets were broken and somecollections belonging to Urartu period were also damaged.

67

(a)

(b)

Figure 7.17. Damaged Kadem Pasha Hatun Kümbet: (a) before and (b) after the earthquake(pictures from Erciş Municipality and Çetin et al., 2011).

Figure 7.18. Stone monuments (toppled) Van Museum (Anadolu Ajansı, 2011).

In Çelebibağ village, a stone wall of castle remains from the Urartu period collapsed
towards South (Figure 7.19).

68

Figure 7.19. Toppled wall of Urartu castle in Çelebibağ village (Erciş).

The Van Castle, which was built in Urartu period in 9th BC, did not suffer any damage
during the October 23, 2011 and the November 9, 2011 earthquakes. It is built over arock ground consisting of limestone (Figure 7.20). There are also some historicalmosques and other historical structures to the south of the castle. There are threehistorical mosques, namely,

Kayaçelebi, Hüsrevpaşa and Süleyman Han mosques,

Hüsrevpaşa mosque was built in 1567 by the famous Turkish architect Mimar Sinan.
The Kayaçelebi mosque was built in 1660 and lost its minaret during the October 23,
2011 earthquake (Figure 7.21). The November 9, 2011 earthquake caused more damage
to the main compounds and minarets and the inner plastering of walls were fallen down.
Süleyman Han mosque is on top of the hill within the castle and built by Magnificient
Sultan Süleyman of Ottoman period and the earthquake did not damage it.

69

Figure 7.20. A view of Van Castle after the earthquake.
(a)

(b)

Figure 7.21. Views of Kayaçelebi mosque (a) before and (b) after the earthquake (pictures from
Ministry of Culture and Tourism of Turkish Republic and Özden et al. 2011).

70

8. DAMAGE TO TRANSPORTATION FACILITIESVan province is served by major highways and railways connected to Tatvan through aferryboat line. Turkish Airlines Company and other major Turkish airline companies
serve between Van and other major cities of Turkey as shown in Figure 8.1. Van
province also neighbors Iran and transportation facilities connect the province to Iranalso. This chapter is concerned with damage to transportation facilities by the October23, 2011 earthquake.

Figure 8.1. Major highways, railways, ports and airports in Van province and its close vicinity.

8.1. Roadways and Roadway Bridges
The major highway connecting Van to Ağrı (D975 & D280) pass through the epicentral
area. In addition, some local roadways run along the shoreline of Van Lake and connect
villages and towns to the major D975, D300 and D280 highways. The D975 and D280
highways run almost parallel to the east shoreline of Van Lake at a higher elevation.
This highway passes over some major rivers such as Karasu, Zilan, İrşat, Çaldıran and71Deliçay. The damage to highways and its bridges by the earthquake was basically quite
light and it did not cause any major obstruction to traffic. The damage to highways androadways was observed as failure of shoulder embankments,
 settlement of approach embankments and piers of bridges,
 failures of slopes adjacent to highways and roadways and rock falls from adjacent slopes and high mountains.
In the followings, the major damages are described.

Embankment failures at several localities, the major ones were observed on the
Van-Ağrı Highway. The embankment (highway itself), seen in Figure 8.2, settled andslightly moved towards Van Lake. Nevertheless, it could be used without any hindrance
to traffic following some repairs the settled and fractured asphalt surfacing of the
highway.

Figure 8.2. Embankment failure on the D975Van-Ağrı Highway

Figure 8.3 shows the damage to shoulder embankments on the roadway betweenDağönü and Özyurt villages and D975 Van-Ağrı Highway near Gedikbudak. The repair

72

works were implemented as seen in Figure 8.3 and the roadway was re-asphalted

Figure 8.3. Failure of shoulder embankment of roadway and D975 Van-Ağrı Highway.

There were many slope failures and rock falls from adjacent slopes or high mountains
along the section of Van-Ağrı Highway between Gedikbudak and Keçikıran as seen in
Figure 8.4. Some of these rock falls from high mountains reached to the Van-Ağrı
Highway. Nevertheless, they did not result in any casualties.

Roadway bridges are generally constructed using cast-in place technique. The
earthquake caused very little damage to bridges. The damage to bridges was due to thesettlement of piers and settlement and lateral deformation of their approachembankments. These type damages of bridges were observed along Van-Ağrı Highway
and other roadways at Karasu and Zilan Rivers (Figures 8.5-8.8). The settlement ofpiers was probably caused the partial liquefaction in the vicinity of bridge piers.

Another interesting slight damage was observed at a small roadway bridge between
Topraktaş and Yüzüncü Yıl University Campus. The approach embankments of thebridge were subjected to ground deformation due to thrust faulting as seen in Figure 8.9.
Vertical bending cracks were observed at wing walls of this small bridge.

73Figure 8.4. Slope instabilities and rock falls along Van-Ağrı Highway.

74

Figure 8.5. Views of damaged Tirleşin bridge over Karasu on Van-Ağrı Highway.

Figure 8.6 Damage to a bridge near Göllü village due to lateral spreading.

75

Figure 8.7. Settlement of piers and lateral deformation of embankments of Zilan Bridge.

Figure 8.8. Settlement of piers of the bridge near Topraktaş village over Karasu River.

76

Figure 8.9. Cracking of wing-walls of a small bridge due to ground deformation caused by thethrust faulting.

8.2. Railways
A major railway line of Turkish Railways (TCDD) connects Van Port to the railway lineof Iran. This railway line connected to the rest of railway network of Turkey through aferryboat line between Tatvan and Van ports. The ferryboat transports the entire train
between Tatvan and Van. The railway line in Van province starts from Van Port andpasses along the southern shore of Erçek Lake and exits Turkey at Kapıköy border gate.
The earthquake caused no major damage to the railway and its bridges. However,ground liquefaction occurred at the Van port and railways were slightly deformed byground liquefaction and its associated ground deformation (Figure 8.10). The interviews
with the railway authorities at the railway station of Van Port informed the authors thatthe slight damage to railways at the port did not cause any disruption of train services.

77

The damage to the station building was almost none, except some cracking related to
the ground liquefaction induced ground deformation.

Figure 8.10. Views of deformed railways and liquefaction at Van Port.

78

8.3. Ports and Breakwaters

Some ground liquefaction occurred at Van Port and there were some slight cracking of
RC components of quay walls and anchorages as seen in Figure 8.11. Nevertheless, theport was functional. The captain of the ferryboat informed the authors that he wassailing to Van when the earthquake hit. Although the earthquake caused a jolt on theferryboat, there was no major problem of huge wave causing the vibration of the ship.

Figure 8.11. Views of slightly damaged Van Port.

Breakwaters at the Van Port and Yüzüncü Yıl University (YYU) Port made of largestone blocks settled and deformed laterally as seen in Figure 8.12. The main reasons forsuch deformations may be related to the settlement of large rock blocks intolake-bottom due to ground liquefaction.

79

(a) Van port(b) YYU port

Figure 8.12. Settlement and spreading of breakwaters of Van and YYU ports due to liquefactionof foundation ground.

Aydan and Ohta (2009) performed some shaking model experiments on breakwaters on
a liquefiable ground following the 2009 West Sumatra Earthquake in Indonesia andobserved that breakwaters can sink into the ground and it may even completely
disappear as seen in Figure 8.13. Similar phenomenon was also observed in 2011
Christchurch earthquake and 2011 Great East Japan earthquake in much large scale.

Figure 8.13. Views of a breakwater model before and after shaking experiment (after Aydan andOhta, 2009).

80

8.4. Airports
The Van airport, also known as Ferit Melen Airport, has a 2750 m long runway along
the shore of Van Lake. The airport is served by Turkish Airlines Company and other
Major Turkish airline companies. In addition, there are also international flights to Iranand Azerbaycan. The earthquake did not cause any damage to its runway and it can beused for emergency operations immediately. However, some structural damage wascaused to the old terminal building especially to its infill walls and window glasses werebroken. Despite it was pointed out that ground liquefaction might be induced in thevicinity of lakeshore, there was no observation of any ground liquefaction in thepremises of Van Ferit Melen Airport.

Figure 8.14. Views of runway and old and new terminal buildings of Van Airport suffered slightdamage (note that the façade of the old terminal building thorn down before earthquake).

81

9. DAMAGE TO LIFELINESThe October 23, 2012 earthquake caused damage to lifelines particularly in Erciş. In
this chapter, the damage to lifelines are briefly summarized as the duration ofreconnaissance was too short for a detailed investigation.
9.1. Electricity
The electricity of Turkey is produced and distributed to main transformation stations byTEİAŞ. From these main transformation stations, the electricity is distributed to thecities and industrial facilities by TEDAŞ. These two originally state companies are now
privatised owned. Figure 8.1 shows the electricity system of Turkey and the electricity
network in the epicentral area.

Figure 9.1. Electricity system of Turkey and the functions of TEİAŞ and TEDAŞ.
The major electricity producing facility is the Zernek1-2 Hydro-electric Power Plant.
The region lost power shortly after the earthquake since it is customary to shut off thepower as soon as a large earthquake happens. After some preliminary checks on the82

location of the earthquake, the power was gradually supplied to the region in order toprevent fires due to short circuits, which could be caused by the collapsed or heavily
damaged structures. The power supply in Erciş was restored in 2 days for 70% and fully
restored in 4 days after the earthquake except heavily damaged areas.

Figure 9.2. Electricity network in the epicentral area.

The earthquake did not cause the collapse of any of the sub-stations although somedamage to some transformers of sub-stations occurred during shaking (Figures 9.3 and9.4). A total of damaged 44 transformers were replaced and 12 transformers were added
to the network in the epicentral area. However, the effects were minimal to thesesubstations and they could be easily handled within a short period of time. Althoughmost of transformers on the elevated utility poles were intact (Figure 9.5), someelevated transformers on pylons in the towns and cities were dislodged/fallen from theirlocations. An example of transformer damage by dislodging in Erciş is shown in Figure
9.6.

83

Figure 9.3. Non-damaged sub-stations in Erciş.

Figure 9.4. A non-damaged sub-station in Van.

(a) Alaköy(b) VanFigure 9.5. Non-damaged elevated transformers.

84

Figure 9.6. Dislodged transformer on a utility pole in Erciş.

Some of poles and pylons of the electricity distribution system in Erciş and somevillages were damaged as a result of ground shaking or foundation failure. Figure 9.7
shows some damage to a utility pole in Van and a utility pole with a transformer inYeşilsu.

Figure 9.7. Tilted and bended utility poles in Van and Yeşilsu.
85

The electricity was back in the evening of the same day in Van city while it was back inthe severly hit Erciş 4 days (26 October 2011, 90%) after the earthquake, except theregions where there were heavily damaged buildings. The 95% of the Erciş town had
electricity restored on November 21, 2011 (Press Release of Van Province Governorship,2011).
9.2. Water Supply and Water Distribution Networks
Water supply was stopped due to pipe damage in Van city following the October 23,
2011 earthquake. However, the damage to water supply network was quite limited bythis earthquake. The November 9, 2011 earthquake caused more damage. The Vanmunicapility had to change some major pipes with a diameter of 800 mm for a 225 mlong connecting to No. 2 water reservoirs. This repair work was done on December 27,
2011 and water supply was shut-down for about 36 hours as a result (Figure 9.8) (Press
Release of Van Municipality, 2011).

Figure 9.8. Repair work of water network of Van City (from Van Municipality, 2011).

The water supply system of Erciş was the most severely hit by the earthquake. Besides
the damage to the pipe network in the downtown of Erciş, the pumping facilities at the86source area near Işıklı village (5km away from Erciş) could not be operated due to thepower blackout. The pump station pumps the spring water over a hill and then the
distribution system runs under the gravity. The diameter of the main pipe with a total
length of 10 km is 500 mm and it branches to 300 mm pipes along major distributionlines and then to 100 mm pipes beneath streets.

For an immediate supply of water to Erciş, first water tanks, provided by İstanbul
Municipality Water Department (İSKİ), were used with a set-up of smaller distribution
systems (Figure 9.9). Later on, the fire department of İstanbul Municipality laid out atemporary network of a hose network, which could stand up to 3.5 MPa internalpressure, to supply clean water to the major distribution points until October 26, 2011
(Figure 9.10). The supplied water was chlorified for sanitation purposed at the major
distribution points. The 95% water supply was achieved in to Erciş by November 28,
2011, except areas of collapses and heavy damages according the press release of the
Van Province Governorship.

Figure 9.9. Emergency water supply in Erciş.

In some villages, there are some facilities to pump up the groundwater. Figure 9.11
shows such a facility in Alaköy village. The inspection of this facilities showed that
there was no sign of damage to the facility.

87Figure 9.10. Temporary water supply system set up by İstanbul Municipality Water
Department .

Figure 9.11. A view of pumping facility in Alaköy.
88

9.3. Natural Gas Network
Aksa Van Gas company is the main supplier of natural gas to the region. No damage
occurred in the of natural gas supply pipe network of Van City due to the October 23,
2011 earthquake. However, it was stopped as a result of power supply blackout
following the earthquake.

The November 9, 2011 earthquake caused a disruption to the natural gas supply in Van
City. The total number of natural gas household in Van city is 7153 in Van city. But they
were reduced to 5440 households due to some slight damage to distribution network andthe shutdown of 7 sub-units in areas where rescue and debris cleaning operations were
underway due to the damage caused by the November 9, 2011 earthquake. The system
is fully restored on November 21, 2011 according to the press release by the Van
Province Governorship.

9.4. Seewage

The diameters of sewage pipes are 1600 mm and 1000 mm beneath boulevards andstreets of large cities, respectively. The sewage system of Erciş was damaged due tosevere ground shaking and lateral spreading (Figure 9.12), while the sewage system of
Van City was almost non-affected. The damage assessment of the sewage system is themost difficult item in the overall damage assessment of lifeline facilities as they are
buried. The systems were checked systematically through water flow states at manholes
in the cities, towns and villages. If there was any blockage, they were repaired. However,some damage may undergo unnoticed unless an indication of damage in the form of89

ground cave-in takes place or material or smell leaks out of the ground.

Figure 9.12 Repair work of sewage in Erciş
9.5. Telecommunications
The TÜRK-TELEKOM and other private companies run the telecommunication system
in Turkey. During the earthquake, the main buildings of the TÜRK-TELEKOM werelightly damaged as seen in Figure 9.13. However, the relay towers of the system were
almost non-damaged. Nevertheless, some telephone lines were damaged as a result of
toppling of the poles of the system caused by the collapse of nearby buildings. The
telephone service was not quite well functioning for three days due to the congestion ofphones to the region as expected. Mobile units and first aid telephone lines were set upby the TÜRK-TELEKOM and other private telephone companies and they were free ofcharge soon after the earthquake, including all public telephones (Figure 9.14).

90Figure 9.13. Slightly damaged main building of the TÜRK-TELEKOM in Erciş.

Figure 9.14. A view of a mobile telecomunication unit of TÜRKCELL in Erciş.

91

10. GEOTECHNICAL ASPECTS OF THE EARTHQUAKE AND ASSOCIATEDGROUND FAILURES AND DAMAGESThe 2011 Van-Erciş earthquake caused an extensive liquefaction and associated groundfailures particularly on the plains along the eastern shore of Van Lake and between Van andErciş, and in the close vicinity of Erciş town. The liquefaction and associated ground failures
resulted from lateral spreading, particularly, close to river beds and lake shore led to damage
to some residential houses, embankments and some bridges. In addition, slope instabilities indifferent sizes also occurred at some locations. In this chapter, first, local site conditions,which have important effects on liquefaction and associated geotechnical damages, werebriefly outlined based on the findings in the previous geotechnical studies performed in Vancity, Erciş town and their close vicinities. Then observations performed by the authors at
different parts of the earthquake-affected region, evaluations on grain size distributions of
the samples collected from ejected sands and silty sands and the lateral spreading induced byground liquefaction, slope instabilities and associated geotechnical damages observed after
the earthquake are given and discussed.

10. 1. Local Site Conditions
As mentioned in Chapter 2, the Holocene deposits in the region mainly consist of alluvial
fan deposits, lacustrine-fluviatile deposits and debris material including loosely-tomoderately cemented gravel, sand, silt and unconsolidated clay horizons, and groundwatertable is generally shallow-seated (Selçuk and Çiftçi, 2007; Özvan et al., 2005, 2008).
Selçuk and Çiftçi (2007), who investigated the liquefaction potential of the Plio-Quaternarysoils in the Yüzüncü Yıl University campus area located at the north of Van city center,classified these soils into for units such as lacustrine, lacustrine-fluviatile, shore-sand andrecent fluviatile sediments with very low p-wave velocities (V p ) varying between 120 and
516 m/s. The lacustrine sediments (phase-1 soils) mainly consist of silty and clayey soils of
CL and CH classes. Lacustrine-fluviatile soils (phase-2 soils) are composed of fine-grainedsoils including silty sand layers and thin gravel layers. The shore-sand sediments (phase-3

92

soils) are poorly graded sands with N 60 values ranging between 13 and 41. These soils with amaximum thickness of 9-10 m observed in the central part of the campus area have finegrained material less than 5% and the groundwater level is near the surface making themsusceptible to liquefaction. The recent alluvial soils (phase-4 soils) along the ancient andrecent rivers and streams are mainly composed of well and poorly graded gravel with sandand silt layers. Typical grain size distribution curves of sandy soils in this sequence together
with the boundaries of lower and upper limits for liquefiable soils are shown in Figure 10.1.
It is clear from this figure that these sandy soils are generally susceptible to liquefaction interms of their grain size distributions. This condition was also confirmed by the factors ofsafety against liquefaction calculated (an earthquake scenario based on M=6.5 earthquake
and a peak ground acceleration of 400 gal) by Selçuk and Çiftçi (2007) as shown in Figure10.2. These investigators also prepared liquefaction potential map of the campus area using
the liquefaction potential index (I L ) and I L classification proposed by Iwasaki et al. (1982).
This map (Figure 10.3) suggests that the soils in the central part of the campus area havehigh liquefaction potential.

Figure 10.1. Typical grain size distribution curves of sandy soils in Yüzüncü Yıl University campus
area and the upper and lower bounds for liquefiable soils (Selçuk and Çiftçi, 2007).

93

Figure 10.2. Results of liquefaction analyses of two selected boreholes at the Yüzüncü Yıl University
campus area (L: Liquefiable, NL: Non-liquefiable, ML: Marginally liquefiable) (Selçuk and Çiftçi,2007).

A preliminary evaluation by Ulusay (2000), based on the data from 12 boreholes drilled at
the Yüzüncü Yıl University campus area in 1984 and grain size distribution curves, thepresence of some loose and fine sand layers at depths between 5.5 and 12.5 m was found.
The thickness of the sand layers increases towards west to the lake shore. In addition, thedata from the boreholes also indicated some dense sand pockets between clay layers.
According to the limited number of boreholes, the SPT-N values generally range between 10
and 20, however, at some depths they reach up to 30-35. The grain size distribution curves ofthe samples taken from sandy layers suggest that they have low amount of fines and fall
between the upper and lower bounds of the grain size curves for liquefiable soils. The depthof groundwater measured in 12 boreholes ranges between 2.55 and 14 m, however, it isgenerally between 5.5 and 9 m. Figure 10.4 shows the locations of liquefaction sites
observed during historical and instrumental periods in Turkey. This map, which has been
constructed based on the records, observations and the data from literature (Aydan et al.,
2000; Ulusay et al., 2000), shows that liquefaction has also occurred at the eastern part of94

Van Lake during the historical earthquakes and the soils in this region are prone toliquefaction.

Figure 10.3. Liquefaction potential map of the Yüzüncü Yıl University campus area (Selçuk andÇiftçi, 2007).

95

Figure 10.4. The locations where liquefaction has been observed in Turkey during historical (before1900) and instrumental (after 1900) periods (Aydan et al., 2000; Ulusay et al., 2000).

The geotechnical boreholes drilled in the settlement area of Van city by Özvan et al. (2005)
showed that this area also takes place on the Quaternary lacustrine and fluviatile sediments.
A view from these deposits taken by the authors of this report during the reconnaissanceafter the Van-Erciş earthquake in the city centre of Van is given in Figure 10.5.

Figure 10.5. A view from the Quaternary sediments in the city centre of Van.

96

These loose sediments have aquifer characteristics and their thickness reach up to about 45
m at the central part of Van city center. Based on this study, the SPT N 60 values are between
20 and 46, 18 and 40, and 14 and 28 between the depths of 3 and 3.45 m, 6 and 6.45 m, and
9 and 9.45 m, respectively, indicating that the soil sequence is moderately dense. These
investigators also mentioned that some sand layers in this area seem to be susceptible toliquefaction in terms of their grain size distributions (Figure 10. 6). The P-wave velocities(V p ) measured in the Van settlement area are low and range between 182 and 551 m/s and
384 and 1024 m/s for the upper and second layers involved in the Quaternary sequence,
respectively. Particularly towards the lake shore, the values of V p show a clear tendency todecrease (Figure 10.7). Due to this, Özvan et al. (2005) concluded that shaking will beconsiderably felt in this settlement during an earthquake.

Figure 10.6. Comparison of the grain size distribution curves of the soils in Van city with the upperand lower bounds for liquefiable soils (Özvan et al., 2005).

Figure 10.7. P-wave velocity map of the city of Van (Özvan et al., 2005).

97

Geotechnical properties and liquefaction susceptibility of soil grounds in Erciş town and its
close vicinity, which are located in the Erciş Plain at the northern shore of Van Lake, werealso investigated by Özvan et al. (2008). As explained in Chapter 2, depth of groundwater inthis plain is between 0 and 12 m and artesian conditions prevail in some wells. The average
thickness of the Quaternary and Plio-Quaternary sequence varies between 10 and 240 m andit increases towards the central part of the plain. The values of N 60 obtained from sandy andsilty layers penetrated by 18 geotechnical boreholes are less than 20 in the areas close to Van
Lake and about 25 at the northern part of the area (Figure 10.8). The coarse grained soils inthis area are generally represented by poorly graded sands and silty sands falling in SM soil
class indicating that they have liquefaction potential in terms of their grain size distributions(Figure 10.9). The factors of safety against liquefaction (F L ) for this area calculated byÖzvan et al. (2008) were smaller than unity indicating that liquefaction potential of the soils
in Erciş town and its close vicinity seems to be high (Figure 10.10).

Figure 10.8. SPT N 60 contour map of the Erciş Plain for the depths between (A) 3.00-3.45 m, (B)
6.00-6.45 m and (C) 9.00-9.45 m (Özvan et al., 2008).

98Figure 10.9. Comparison of the grain size distribution curves of the coarse grained soils in Erciş
and its close vicinity with the upper and lower bounds for liquefiable soils (Özvan et al., 2008).

Figure 10.10. Contours of factor of safety against liquefaction for Erciş town (Özvan et al., 2008).

99

The local site conditions briefly mentioned above indicate that the Holocene deposits of theearthquake-affected region seem to be susceptible to liquefaction under dynamic loads
generated by earthquakes
10.2. Liquefaction and Associated Ground Failures

10.2.1 Liquefaction and its effects on structures
In this earthquake, liquefaction and associated ground deformations were evident andwidespread sand boils and liquefaction fissures were observed particularly in Erciş Plain(Çelebibağı and Kasımbağı villages, and along Zilan stream) at the northern part of Van
Lake and the flood plain of the Karasu River (Topraktaş, Arısu, Göllü, Tevekli, Çitören,Mollakasım Güvençli and Alaköy villages), Van Port and Esenkıyı at the north of Van city,
and alluvial shore plains. Lateral spreading was quite extensive at Çelebibağı (west of Erciş)and Topraktaş (at NW of Van city) villages. Some of these liquefaction locations were visitedby the authors during the reconnaissance and the information for the other liquefied sites
were compiled from the quick reports of various investigators. The locations of the liquefied
sites and associated lateral spreading are shown in Figure 10.11.
One of the sites, where widespread liquefaction was observed, is the Van Port (Figure
10.12a). In this area, there were evident sand boils with different diameters, reaching up to a
maximum value of 160 cm, and fissures (Figure 10.12b). Ejected sands were also commonly
observed along the contacts of the pavement stones between the rails (Figure 10.12c). Clear
evident of liquefaction-associated settlements with a vertical displacement of about 5 cm arealso observed at the station and quay wall (Figure 10.12d).
Settlement of a bridge at the southern entrance of Topraktaş village (Figure 10.13a) and sandboils and fissures and lateral spreading along the Karasu (Evlengaz) Stream flowing under
this bridge were the clear evidences of liquefaction (Figure 10.13b,c). In addition, commonliquefaction sand boils were also observed on a flat area about 1 km far from this village,
between the stream and road (near Topraktaş-Arısu road).

100

Figure 10.11. Map showing the geotechnical aspects, surface rupture of the Van-Erciş earthquakewith water level changes in Lake Van.

101

(a)

(b)

(d)

(c)

Figure 10.12. (a) A view from Van port, (b) liquefaction fissures and sand boils, (c) settled stationbuilding and (d) ejected sand along the contacts of pavement stones between rails (Van Port).

102

(a)

(b)
(c)

Figure 10.13. Views from liquefaction in Topraktaş village: (a) a bridge settled due to liquefaction,(b) liquefaction fissures parallel to the Evlengaz Stream, (c) sand boil.

103

In this area, the sand boils and fissures were oriented parallel to the stream (Figure 10.14).
The local people emphasized that ejected soil and water raised up to 4-5 m to the surface
during the earthquake at this flat area. Based on visual inspections, the ejected sands in thisarea have similar characteristics with those observed at the southern entrance of Topraktaş
village and also involve very small-sized pebbles. Since there is no any structure located inthis area, liquefaction-induced damages did not occur.
(a)

(b)

Figure 10.14. (a) Liquefaction and (b) liquefaction fissures occurred near the road between Topraktaş
and Arısu villages.

One of the other important liquefied sites is located about 1 km south of Göllü village (nearthe road between Göllü and Güvençli villages). At this location, in addition to sand boils(Figure 10.15a), the bridge on the road and the water canal were affected by liquefaction(Figure 10.15b). Although sand boils are not observed, ground cracks parallel to the water
canal also indicate liquefaction in Güvençli village (Figure 10.15c).
Çelebibağ village, particularly its İnönü district, which is located in the Erciş Plain at thewest of Erciş town, is the location considerably affected by liquefaction. Although someejected sands filling the fissures are observed at limited number of locations, widespread

104

lateral spreading cracks and associated ground movements were the main evidents ofliquefaction at this site (Figure 10.16). Based on the information from local people andsurface observations by the authors, Çelebibağ village is situated on a soil sequence
consisting of a sand layer at the top which is underline by a clay layer and a second sandlayer. But the order of the layering changes at some locations and the clayey soil represents
the cap soil. Probably due to the presence of a clayey cap soil and probably the occurrence ofliquefaction in the underlying sand layer, sand boils are not commonly observed in this site.
In addition, a crack and settlement on the right abutment of the bridge on the İrşat Stream
crossing the road between Erciş and Adilcevaz indicate liquefaction (Figure 10.17). Sandboils in the alluvium of this stream near to the bridge was also reported by Çetin et al. (2011).
(a)

(b)

(c)

Figure 10.15. (a) Sand boil and (b) a bridge damaged due to liquefaction on the road between Göllü
and Güvençli villages, (c) liquafaction in Güvençli village.

105

(a)

(b)

Figure 10.16. (a) Lateral spreading crack filled by ejected sand, (b) sand boil (Çelebibağ village).

Figure 10.17. Crack and settlement on the right abutment of the bridge on the İrşat Stream betweenErciş and Adilcevaz indicate due to liquefaction.

As mentioned in Section 10.1, Özvan et al. (2008) considered the maximum groundacceleration as 0.35 g and evaluated the liquefaction potential of Erciş town and its close
vicinity using the borehole data. They found that the ground, on which Erciş town is located,would liquefy entirely (Figure 10.10). On the contrary to their findings, no widespreadliquefaction has been experienced in Erciş during the Van-Erciş earthquake. It is also very
difficult to verify the estimations by Özvan et al. (2008) as there was no strong motion
record at Erciş. As the maximum ground acceleration recorded in Muradiye town (at the east106

of Erciş) was 0.2g, it is expected that some partial liquefaction might occur. The settlementof some buildings (Figure 10.18), reported and observed in Erciş town, may imply partialliquefaction did occur. İTÜ (2011) also conclude that some settlements observed in thevicinity of Clock Tower in Erciş town are probably due to softening and collapsing of thesoil ground.

Figure 10.18. Settlement of a building probably due to liquefaction in Erciş town (after JMO, 2011).

Selçuk and Çiftçi (2007), who evaluated the liquefaction potential of the soils in the campus
area of Yüzüncü Yıl University, estimated that the central part of the campus has highliquefaction potential, and the area between the central part and the lake shore line has low
liquefaction potential based on an earthquake scenario (M=6.5 and a max = 400 gal) (Figure10.3). Except a limited area at the University Port, no evidences of liquefaction wereobserved in this area. As there was no strong motion record for Van, it is extremely difficult
to verify the estimations by these investigators. However, some movements probably due tolateral spreading on the breakwater of the University Port on the lakeshore (Figure 19)
indicate that some partial liquefaction might have occurred which may partly confirm theliquefaction estimations by Selçuk and Çiftçi (2007). In addition, pipe breaks at many
locations in the water transmission system of Yüzüncü Yıl University due to groundsettlement were reported by KOERI (2011).

107

(a)

(b)

(c)

Figure 10.19. Movements probably due to lateral spreading on the breakwater of the University Port.

Some pictures from the other liquefied sites, to which the authors of this report couldn’t visit
due to limited time, were compiled from the reports of various reconnaissance teams and areshown in Figure 20. İTÜ (2011), Akyüz et al. (2011) and JMO (2011) reported liquefaction
and lateral spreading occurred in an area 3 km far from Alaköy village (Figure 20a). Basedon the interview by the ITÜ reconnaissance team (İTÜ, 2011) with local people, at thislocality, liquefied soil and water raised up to a few meters above the surface during the main
shock.

10.2.2. Lateral spreading and its effects on structures
In this earthquake, most important effect of liquefaction was the lateral spreading of theground, particularly along river and streambeds and partly lakeshore. Lateral spreading
cracks and resulted ground deformations are generally observed at most of the liquefied sites
mentioned in sub-section 10.2.1. Lateral spreading was particularly quite extensive in108Çelebibağ and Topraktaş villages and their close vicinities. The locations of the lateral
spreading sites were also shown in Figure 10.11.
(a)

(b)

(c)

(d)

Figure 10.20. The some other sites where liquefaction observed: (a) Alaköy (JMO, 2011), (b)Esenkıyı (Göldüzü) (Emre et al., 2011), (c-d) Tevekli (Akyüz et al., 2011).

The ground cracks resulted from lateral spreading at the Van Port were in N-S direction
parallel to the lake shore, and as also confirmed by the port personnel, a relative movementon the quay wall was observed (Figure 21a, b). The length of some cracks reached up to 70
m and the separation of the cracks were between 1 and 5 cm (Figure 10.21c). At the Van Port,
lateral spreading also caused separation between the rails about 15 cm (Figure 10.21d).

109

(a)

(b)

(c)

(d)

Figure 10.21. (a-b) Evidences of relative movement of the quay wall (c) separation of 5 cm lateral
spread crack, (d) separation between rails due to liquefaction at Van Port.

Lateral spreading occurred particularly along the left bank of the Evlangaz Stream near
Topraktaş village resulted in ground cracks filled by the ejected sand with a direction of
N75E parallel to the stream (Figure 10.22a). Based on the measurements by the authors
between these cracks, a total displacement of 1 m due to lateral spreading was found at thislocality. The lateral spreading cracks on the plain at the southern entrance of Topraktaş
village occurred between the Topraktaş-Arısu road and the stream (Figure 10.22b). The total
displacement at this location was measured about 80 cm and the trend of the cracks was
N70W parallel to the stream. Except the bridge on the Evlangaz Stream (Figure 10.13a),
fortunately, since there is no any settlement and structure in this area, no geotechnicaldamaged occurred.

110

(a)

(b)

Figure 10.22. Lateral spreading cracks parallel to Evlangaz Stream; (a) Topraktaş village and (b) near
the road between Topraktaş and Arısu.

The bridge and water canal on the road between Göllü and Güvençli villages were damaged
by lateral spreading. The ground cracks resulted from lateral spreading were in N-S direction
and caused failures on both banks of the water canal and damage (cracks on the culvert) tothe bridge (Figure 10.23). The separation between the lateral spreading cracks was about 20
cm. The bridge suffered more damage due to settlement and rotation and more tilting of its
abutments, as well as the extensive cracking and settlement of approach abutments due toground liquefaction.
Çelebibağ village, at the west of Erciş town, is the most important site where widespreadlateral spreading occurred and resulted in heavy damages to residential houses, a concretewater canal (Figure 10.24a-c). The area affected by lateral spreading is approximately 350 m
long and 150 m width. The trend of lateral spreading cracks was in N-S and/or N20S
direction. In this area, the total displacement, which was induced by lateral spreading
approximately towards south and measured from the ground cracks by the authors, was 1.5
m and inclination of the ground was 30 (Figure 10.24d). In addition, some localized damages
to buried water pipes in Çelebibağ village due to lateral spreading were also reported by
KOERI (2011). On the other hand, the piers and abutments of the Evlangaz Bridge, on theroad between Van and Ağrı cities (100 m west of Van E-type prison), was slightly damaged
due to settlement and lateral spreading of ground (Figure 10.24e).

111

(a)

(b)

(c)

(d)

Figure 10.23. Damages to the road bridge and water canal between Göllü and Güvençli due toliquefaction and lateral spreading.

10.2.3. Evaluation of liquefaction and lateral spreading
The authors have gathered some samples from sand boils observed during thereconnaissance (Figure 10.25a). Generally the ejected soils were in gray color and composedof sand, silty sand and sand with low amount of small pebbles. These samples were collectedfrom Van Port, Çelebibağ, Topraktaş and Göllü villages. Besides, additional ejected sandsamples were obtained from Dibekdüzü and Mermit meadow by Dr. Onur Köse of Yüzüncü
Yıl University to be used in this study. Their grain size distribution analyses, using sieve andhydrometer methods, were carried out in the soil mechanics laboratories of Hacettepe andPamukkkale Universities. It is clear from Figure 10.25b that, although some samples havehigh fine content, they are still within the easily liquefiable bounds.

112

(a)

(b)

(c)

(d)

(e)

Figure 10.24. Lateral spread and resulted damages in Çelebibağ village: (a) damaged canal, (b-c)
damaged residential houses and (d) movement and cracks due to lateral spreading, and (e) damage topiers and abutments of the Tirleşin Bridge due to settlement and lateral spreading of ground.

113

(a)

(b)

Figure 10.25. (a) Sampling from ejected sand (Van Port), (b) comparison of grain-size distributionsof the samples obtained from liquified soils in various sites of the erathquake-affected region withknown bounds for liquefiable soils (Port and Harbour Research Institute, Japan, 1997).

Aydan et al. (1998) compiled some data on the locations of earthquakes and developed some
empirical relationships between magnitude of earthquake and hypocenter distance forliquefaction and non-liquefaction sites. These relationships are given in Fig. 10.26. The
empirical lines in this figure may also be regarded as non-liquefaction to light, light tomoderate to severe liquefaction boundaries in Turkish earthquakes. Figure 10.26 shows
empirical relations for the magnitude and hypocenter limit distance for liquefaction withobservations carried out by the authors after the Van-Erciş earthquake. The observations fall
into the domain of liquefaction predicted by empirical relations proposed by Aydan et al.
(1998) and Aydan (2007). It should be noted that the relations by Aydan (2007) considers the
position of observation point with respect to the earthquake fault.

114

Figure 10.26. Comparison of empirical relations for magnitude and liquefaction limits withobservations at liquefied sites performed in the earthquake region.

Aydan et al. (2008) proposed an approach to estimate amount of lateral spreading using thestrong motion records. A sample computation was carried out for different base inclinationof liquefiable layer using the records at Muradiye strong motion station and results areshown in Figure 10.27. The amount of lateral spreading is about 69 cm for an inclination of
3% while it becomes about 19 cm for the inclination of 1%. As the inclination of liquefiable
layer was probably more than 3% at Çelebibağı (Erciş) (Figure 10.24d), these computational
results can explain the possible reason for large deformation at that locality.

Figure 10.27. Computed lateral spreading for three inclinations using the records taken at Muradiye.

115

10.3. Slope and Embankment Failures
Many slope failures were observed in the epicentral area. Most of the slope failures occurredon the hanging wall-side of the earthquake fault (Figure 10.11). The dominant types of slope
failure were rock falls and flows. Some slope instabilities were recognizable only from thetension cracks observed at their crests, rather than fully displaced mass movements.
One of the largest slope failures occurred in the vicinity of Topraktaş village on the rightbank of the Karasu Stream. This instability developed in a relatively weak slope forming
material (Figure 10.28a) and the height of the failed slope was greater than 30 m. Figure
10.28b shows numerous rock falls from basaltic slopes near Keçikıran which is close to thenorthern shore of Van Lake. Local rock falls from the road cut between Topraktaş and Arısu
villages also occurred (Figure 10.28bc. Some of the rock falls from the road cuts in Van
formation at the north of Gedikbulak village reached to the Van-Ağrı highway (Figure
10.28d). Nevertheless, they did not result in any casualties.
Typical earthquake-triggered and large-scale slope instability was observed on a hilly
topography between Yeşilsu village and Amik Castle on the eastern shore of Lake Van(Figure 10.29). The slope failed is composed of weak, weathered and partly soft material.
The villas under construction on this slope subjected to heavy damage due to slope
movement. Bending cracks on the columns of these buildings and tension cracks on the crestof the slope were evident. Model experiments on rock slopes (Aydan et al., 1991, 2003)
clearly show that accelerations are larger at the top of the slope and they are amplified near
the slope crest. This situation suggests possible ground amplification at the cliff sides due totopographical effects. This effect was clearly observed in the city of Bingöl and a village
during the 2003 Bingöl earthquake (Ulusay and Aydan, 2005). Probably amplification effectdue to earthquake and sloping ground might be the main reasons of the damage to thesevillas.
At some locations along the eastern lake shore at the north of Van, some slope instabilities,
generally in the form of rock falls, also occurred. One of them is the local rock falls observed
near to Özyurt village (Figures 10.11 and 10.30a). The other instability occurred in the116lacustrine terraces on the road between Dağönü and Mollaksım villages (Figure 10.30b).
However, these instabilities did not affect the road parallel to the lake shore. In addition tothese, some instabilities in old landslide areas at the east of Çomaklı and Meydancık villages
which were identified from the tension cracks by Emre et al. (2011) and rock falls from thecrown of the Özyurt landslide complex (YTÜ-DBAM, 2011) were also reported.
(a)

(b)

(c)

(d)

Figure 10.28. Slope failures trigerred by the Van-Erciş earthquake: (a) slope failure near Topraktaş,and rock falls. (b) near Keçikıran and (c) between Topraktaş and Arısu, and (d) along the slope of theroad cut (Van-Ağrı highway).

117

(a)

(b)

(c)

(d)

(e)

Figure10.29. Natural slope failure between on the coast of lake shore between Amik Castle andYeşilsu village and damaged villas under construction.

Figure 10.31 compares the empirical relations between the earthquake magnitude and limitsof slope failures for coherent and disrupted states. The observations from the Van-Erciş
earthquake region are within the bound of the empirical bounds proposed by Aydan (2007)
and empirically drawn line by Keefer (1984). The relations proposed by Aydan (2007)118

considers the effect of fault orientation with respect to the observation point
(a)

(b)

Figure 10.30. (a) Rock falls near to Özyurt village, (b) sliding between Dağönü and Mollakasım

Figure 10.31. Comparison of observational results with empirical relations between earthqauke
magnitude and epicentral limit distance for slope failures.

Embankment failures were observed at several localities. Major embankment failures wereobserved on the Van-Ağrı Highway. Figure 8.2 shows one example of embankment failure.
The embankment seen in this figure moved towards the lake and settled.

119

11. TRIGGERED VAN-EDREMIT EARTHQUAKE

11.1. Introduction
Van- Edremit earthquake occurred at 21:23 local time on November 9, 2011. Although themoment magnitude (M w ) of this earthquake was only 5.6 (M L =5.6-5.7), it caused heavy
damage in the city of Van and added to the distress caused by the earlier M w 7.0-7.2 VanErciş earthquake on October 23, 2011. The epicenter of this earthquake (38.4288N, 43.229E)
is located near Edremit, a town on the eastern shore of Van Lake about 16 km to the south of
Van city center (Figure 1.2). This earthquake is considered to be triggered by the effect of
the crustal stress state following the October 23, 2011 event. This chapter outlines various
aspects of the Van-Edremit earthquake of November 9, 2011. Because the earthquake
occurred in the same region; geology, seismo-tectonics and local site conditions are notrepeated herein. This chapter mainly involves seismic characteristics of the earthquake andevaluation of strong ground motion characteristics, description of both structural andgeotechnical damages, and the effect of non-appropriate repair of the buildings is also briefly
discussed.

11.2. Focal Mechanism and Seismicity
Figure 11.1 shows the focal mechanisms obtained by various institutes such as USGS (2011),
ERD(2011), KOERI(2011) and HARVARD(2011). All focal mechanisms solutions

indicated that the faulting mechanism of this earthquake was due to strike-slip faulting.
Although the solutions yield two fault planes, NW-SE trending fault may be the causative
fault. In view of the seismicity since November 09, 2011 shown in Figure 11.2 andrecognized fault traces in the field, a sinistral NW-SE tending steeply dipping fault should be
the causative fault. This fault probably is located to the east of Edremit.

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Figure 11.1. Geology of Van and its close vicinity and faulting mechanisms for the Van-Edremit
earthquake estimated by different institutes (base map from Özkaymak et al., 2004).

Figure 12.2. 2 Seismicity of epicentral areas of November 09, 2011 and October 23, 2011 sinceNovember 09, 2011.

121

11.3. Characteristics of Strong Motions
During this earthquake, strong ground motions were recorded by National Strong Motion
Network of Turkey operated by the Earthquake Research Department (ERD) andtemporarily installed network by Kandilli Observatory and Earthquake Research Institute(KOERI) following the October 23, 2011 Van-Erciş earthquake. KOERI also installed strong
motion stations on both soil (VNKEA) and rock (VNS). The maximum ground acceleration
recorded by the ERD (VBIM) and KOERI (VNKEA) at two soil ground sites in the City of
Van are 0.27 g and 0.29 g, respectively (Figure 11.2). Figure 11.3 compares the acceleration
records and acceleration response spectra of motions recorded at soil stations while Figure11.4 compares recorded motions and corresponding spectra at soil (VNKEA) and rockstations (VNS). Although the amplitudes of waves are slightly different, the records are quite
similar to each other. Furthermore, the accelerations are amplifed for periods of 0.1-0.15s
and 0.35-0.4s.

Figure 11.3. Locations of strong motion stations (base map from Google earth)122

Figure 11.4. Comparison of the acceleration records and their acceleration response spectra of ERD
and KOERI stations in Van.

Figure 11.5. Comparison of the acceleration records and their acceleration response spectra on soil
and rock stations in Van.

123

The comparison of raw acceleration records and their acceleration response spectra indicatedthat the amplifications were 2.4 and 3.6 times, respectively. Furthermore, the maximum
spectral accelerations roughly correspond to those of periods of 0.36-0.4 s, which generally
corresponds to the natural periods of 6-8 story reinforced concrete buildings.
Figure 11.6 shows the attenuation of strong motions recorded by the ERD and KOERI withthe empirical relations of Aydan (2001), Aydan and Ohta (2011a) and Ulusay et al. (2004).
The maximum ground acceleration on soil is well predicted by the attenuation relation
proposed by Aydan (2001) while the relations by Aydan and Ohta (2011a) using the shear
velocity of Van strong motion station and Ulusay et al. (2004) underestimated the maximum
ground accelerations by 30-40% less.

Figure 11.6. Comparison of some empirical attenuation relations for maximum ground accelerationand velocıty with observations

Aydan and Ohta (2011b) modified slightly their original method called EPS method (Ohtaand Aydan, 2007) to estimate the behavious of ground during earthquake and to compute thepermanent ground deformation from strong motion records. This method wass applied tonear field stations, specifically VBIM-ERD, EDR-ERD, VNS-KOERI and VNKEA-KOERI,
around the epicentral area Figure 11.6(a) compares the responses for three different
directions in the City of Van, which is located on the mobile side of the fault. It is interesting124

to note that the top soil may even move opposite direction compared to that of rock base.
This further implies that ground shaking may cause the plastic deformation of top soil layer.

Figure 11.7. Displacement responses of strong motion stations computed from EPS method (a) The
City of Van), (b) Rock ground at Edremit and Van

11.4. Casualties and Structural Damage
This earthquake resulted in the loss of 40 lives as it happened at 21:23 in the evening. On theother hand, the 23 October 2011 Van-Erciş earthquake resulted in the loss of 604 people andoccurred at 13:41 on Sunday. Figure 11.8 shows the relations between local magnitude andcasualties. The estimations for upper (UL), mean (ML) and lower (LL) limits are computedfrom the following function proposed in this article using the data from various catalogues
for Turkey (i.e. Ergin et al. 1967; Soysal et al. 1981; Eyidoğan et al. 1991).

125

N  A( M L  B) c

(12.1)The values of constants A and c are 2 and 7, while the values of constant B are 3.5, 4.5 and
5.5 for UL, ML and LL, respectively. The main reason for such large ranges may be related
to the time of earthquake, quality of buildings and ground conditions.

Figure 11.8. Relation between local magnitude of earthquakes and casualties.

This earthquake caused the collapse of the 30 reinforced concrete buildings, most of which
had already suffered substantial damage during the 23 October 2011 earthquake (Figures 11.
9- 11.11). Fortunately, 23 of the collapsed buildings had been evacuated due to the damage
caused by the earlier earthquake. However, two hotel buildings were open during this second
earthquake and some of the people staying there lost their lives (Figure 11.9). This
earthquake also caused additional damage to some buildings. The collapsed hotels had
cracks following the October 23, 2011 earthquake and they were cosmetically repaired. The
authors noticed such non-structural repairs in the city of Van during their reconnaissance for
the October 23, 2011 earthquake (Figure 11.12).

126

(a)

(b)

Figure 11.9. Views of Bayram Otel (a) before and (b) after the Van-Edremit earthquake (Anadolu
Ajansı, 2011).
Şekil 11.9. Bayram Oteli’nin Van-Edremit depremi öncesi (a) ve sonrası (b) görüntüleri (Anadolu
Ajansı, 2011).

The major causes of the heavy damage to reinforced concrete buildings were basicallysimilar to the previous observations during previous earthquakes in Turkey:(a) Quality of construction materials,(b) Lack of implementation of design codes (bars, stir-ups, proper column-beamconnections, tie-beams, good foundation etc.),(c) Existence of soft-floor (weak-floor),(d) Pounding,(e) Lack of ductility,(f) Poor integrity of RC frame with in-fill walls,(g) Quality of workmanship,(h) Poor ground conditions.
Furthermore, cosmetic non-structural by re-plastering of cracked beams, columns, infillwalls and beam column connections had disastrous effects. Similar problem was observed inbuildings damaged by the 1999 Kocaeli earthquake in Düzce during the 1999 Düzce
earthquake (Aydan et al., 2000a and 2000b).

127

Figure 11.10. Views of a collapsed reinforced concrete building in Van (Van-Edremit earthquake)(Anadolu Ajansı, 2011).

Figure 11.11. Views of heavily damaged reinforced concrete buildings of DSI in Van (Van-Edremit
earthquake) (Photos: Ayhan Koçbay).

128

Figure 11.12. Cosmetic repairs applied to a damaged RC building in Van on November 5, 2011 after
the Van-Erciş earthquake.

11.5. Geotechnical Aspects and Associated Damages
This earthquake also caused some ground liquefaction along the Van lakeshore (Figure 11.13a) andthe ground liquefaction again occurred at the Van Port, where the ground liquefaction was also
observed following the 23 October 2011 earthquake. Figure 11.13b shows the grain size distributionof the boiled sand, which was sampled from the Port of Van by Dr. Onur Köse of Yüzüncü Yıl
University to be used in this study. The grain size distributions in Figure 11.13b are within the mostliquefiable bounds with high percentage of fine content and very similar to those observed in the
Van-Erciş earthquake at the port area.

129

(a)

(b)

Figure 11.13. (a) Views of boiled sand in Van Port due to the M5.6 Van-Edremit earthquake and (b)its grain size distribution.

Figure 11.14 shows the empirical relations between earthquake magnitude (M w ) andhypocentral distance of liquefaction location proposed by Aydan et al. (1998) and Aydan(2007) with the observation in this earthquake. The observation is within the proposed
empirical limits. However, it is also noted that despite the smaller magnitude (M5.6) of thisearthquake, it caused ground liquefaction at a location where previously liquefaction has also
occurred and this is the first time for liquefaction occurred during an earthquake with amagnitude smaller than 6 experienced in Turkey.

130

Figure 11.14. Comparison of empirical relations for magnitude and liquefaction limits withobservations at liquefied site (Van Port) performed in the earthquake region.

13112. CONCLUSIONS AND RECOMMENDATIONSIn this report, the authors have described the site observations and information they
have gathered during their investigation, and made some assessments on different
aspects of the October 23, 2011 and November 9, 2011 Van-Erciş and Van-Edremit
earthquakes, respectively. This study is an inter-disciplinary work of various
disciplines of science and engineering such as geology, seismology, tectonics,
engineering geology, and geotechnical and earthquake engineering. This investigation
was carried out to cover both engineering and scientific aspects of this earthquake.
The following conclusions are drawn from this study.
This earthquake was caused by thrust type faulting, which is generally rare for Turkey,
but it is typical of faulting mechanism for this tectonic province of Turkey. The thicksoil and weathered rock above the rock base diluted the deformation of ground over alarge zone so that a clear fault scarp is not observed. The likely deformation of soft
soil and weathered rock should be similar to that seen in Figure 5.4e. The failures ofslopes and embankments and rock falls and ground liquefaction may also be
indications of diluted ground deformation caused by the earthquake fault.
From the seismicity, it seems that a wedge like body bounded by fault planes FP1 andFP2 shown in Figure 5.2 is uplifted. As a result of this movement, the uplift of thenorthern shoreline of Van Lake should have occurred.
The Van-Edremit earthquake is not an aftershock of the October 23, 2011 Van-Erciş
earthquake. It has a different faulting mechanism. However, there is no doubt that it
was triggered due to the variation of crustal stresses induced by the October 23, 2011
earthquake. This example also shows that the necessity of a clear definition ofaftershocks.
The strong motions induced by this earthquake have a strong directivity effect andErciş town with a population of 100,000 people suffered heavy damage and casualties
as it was on the hanging wall side of the fault.
Although the magnitude of the triggered Van-Edremit earthquake was small, high132

ground motions with a strong directivity effect were recorded. The maximum groundaccelerations on soil ground were amplified up to 3.6 times that on rocky ground.
The main causes of heavy damage or collapse of reinforced concrete buildings are
similar to those observed in previous earthquakes occurred in Turkey. These are poor
workmanship, construction mistakes, negligence and lack of moral, lack ofimplementation of seismic codes in structural design, resonance phenomenon due toground conditions, soft (weak) floors, pounding of adjacent structures andliquefaction of ground. This earthquake also showed that the non-structural repairs ofbuildings are disastrous and must be avoided. Except buildings, the damage tocommon civil engineering structures such as roadways, bridges, tunnels and dams wasalmost none or slight.
From observations, it is strongly suggested that the construction practices inearthquake prone areas of Turkey should be changed from that of reinforced concrete
moment framed system to reinforced concrete shear-wall system. Such a change
would reduce drift ratios and prevent collapse of buildings, thus averting loss of lives
and property. There are some golden rules how to construct masonry buildings inearthquake-prone areas, which are outcomes of experiences gained from thelong-history of seismicity of Turkey.

These rules can be summarized as follow:(a) Built on a base-mat concrete or firm base (if ground condition is poor)(b) Roof should be light (toprak dam (earthen roof)) is not desirable)(c) Use hatıls (timber or concrete beam) at each 1 m interval at the top of the wall.
Reinforcement is desirable if possible. They are effective at corners even they are
short(e) Use lime (cement)-based mortar with saman (straws) in kerpiç (adobe) bricks(original idea of fiber-reinforced concrete/shotcrete comes from this concept)(h) Plaster walls in order to prevent water diffusion into kerpiç (adobe) bricks
The site investigations clearly showed that the epicentral area is vulnerable to damage
from ground liquefaction and slope failures. The anticipated ground liquefaction did
occur in Erciş town and the north of Van city and settlement along rivers. However, theintensity of ground liquefaction was not that high.

133

The Van-Edremit earthquake with a magnitude of 5.6 is probably the smallest
magnitude earthquake to cause liquefaction in Turkey so far. Once again, thisearthquake showed that ground liquefaction can occur in the same location repeatedly.
Very thick soft sedimentary deposits exist along the shores of Van Lake. Any new
developments of housing and road construction must consider the effect of such soft
ground conditions.
The earthquake area is mountainous and it may suffer from rock falls and huge slope
failures.

134

ACKNOWLEDGEMENTS
The authors would like to sincerely express, their thanks and gratitude to thefollowings without their help this investigation could not be very fruitful within a very
short period of time.
The most findings described here are the outcomes of the survey by the Turkish andJapanese experts dispatched by the Japan Society of Civil Engineers (JSCE). In
organizing the team, the Disaster-Information Network among JSCE, AIJ and JAEE
(Chairman, Prof. K. Kawashima of the Tokyo Institute of Technology) took the
initiative.
Assist. Prof. Dr. Şehabettin Öztürk (Yüzüncü Yıl University and Chairman of Van
Branch of the Chamber of Architectures of Turkey) for his kind information andguidance by during reconnaissance visit to the earthquake affected region, and Assist.
Prof. Dr. Onur Köse (Geological Engineering Department of Yüzüncü Yıl University)
for his kind enthusiasm for providing information and samples from some liquefied
soils.
Assoc. Prof. Dr. Ergun Tuncay, Res. Assist. Elif Avşar, laboratory technicians Ozgür
Erol and Ahmet Bay from Hacettepe University, and Assist. Prof. Dr. İbrahimÇobanoğlu and Res. Assist. Sefer B. Çelik from Pamukkale University for their kind
helps in geomechanical laboratory tests. Dr. Ayhan Koçbay from the General
Directorate of State Hydraulic Works (DSİ) for the information and photographs ofthe damaged buildings of the DSİ Van Branch he provided.
The last, but not the least, the people of the earthquake stricken area for theircooperation in gathering information on the extent of damage and guiding the authors
to places of great significance, kindness and generosity even though they suffered themost by losing their properties as well as their beloved ones. The authors wish thequick recovery to their ordinary lives and want to end this report with a heartfelt
condolence wishes. This report is dedicated to Dr. Atsushi Miyazaki, who was fromJapan and working in Van for rescue studies and lost his life during the Van-Edremit

135earthquake of November 9, 2011, and to the people lost their lives in Van-Erciş and
Van-Edremit earthquakes.

136

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