TSUNAMI HAZARD ASSESSMENT IN ISTANBUL USING BY HIGH RESOLUTION 
SATELLITE DATA (IKONOS) AND DTM 
B. Alpar*^ *, C. Gazioglu *. Y. Altinok“, Z.Y. Yücel^, S. Dengiz* 
? Istanbul University, Institute of Marine Sciences and Management, 
34116 Vefa Istanbul, Turkey (alparb@istanbul.edu.tr) 
b [Istanbul University, Institute of Marine Sciences and Management, BERKARDA Remote Sensing and GIS 
Laboratory, 34116 Vefa Istanbul, Turkey (cemga, zyy)@istanbul.edu.tr 
* Istanbul University, Engineering Faculty, Avcilar Istanbul, Turkey - yaltinok@istanbul.edu.tr 
? INTA SpaceTurk, PB.18 Haymana Yolu 12km. 06830 Golbast Ankara, Turkey (sdengiz@spaceturk.com.tr) 
Commission TS, WG VII/5 
KEY WORDS: Earthquake, Coast, Hazards, Bathymetry, DEM/DTM, IKONOS, High Resolution, Land Cover 
ABSTRACT: 
Historical tsuna 
mi events have impacted the Istanbul coasts along the Sea of Marmara. Offshore seismic sources may trigger these 
tsunamis directly or through coseismic underwater failure. The 1999 izmit Bay tsunami led to more comprehensive analyses of these 
events which are generally caused by underwater failures close to the target coastline. Waves so generated can arrive at nearby 
coastlines in minutes, causing extensive damage and loss of life. Here this paper prop 
ose, on the basis of tsunami models in the Sea 
of Marmara and methodology used internationally, first generation tsunami inundation maps for the areas along the southern coast of 
Istanbul using by High Resolution Satellite Data (IKONOS) and Digital Terrain Data (DTM). Such maps and images for selected 
areas help to und 
hazard. 
1. INTRODUCTION 
The coastal area of the Sea of Marmara is subjected to a near- 
field hazard — a tsunami generated in something under 2 hours 
tsunami travel time to the locality. Such a tsunami can 
propagate in any direction and thus, dependent on the location 
of the source, path of propagation and near-shore morphology 
form a risk to any vulnerable coastline. 
Throughout history, Istanbul, which is the most populated 
historical city of Turkey, has been beset by different-size 
tsunamis. In the case of tsunami hazard, the southern coastal 
area of Istanbul is subjected to a near-field hazard. Different 
from far-field tsunamis, it may be difficult to generalise the 
effects of near-field tsunamis, because there is a large 
variability over short distances of the height of tsunamis and 
their destructiveness. The long interval between events in a 
specific position makes the problem more complicated. 
Even the historical records of near-field tsunamis is often 
incomplete due in large part to inadequate data and data of 
questionable quality, especially in the case of older events, 
there are many events well documented for our case. During 
last 1600 years, at least 21 historic tsunamis are known to be 
felt in Istanbul (368, 407, 447, 477, 478, 480, 557, 740, 989, 
1231, 1265, 1332, 1343, 1344, 1419, 1509, 1571, 1646, 1766, 
1878 and 1894). Nearly half of them impacted its coasts 
(Altinok et al., 2001). 
In 407, ships were damaged in Istanbul. In 557, 1231, 1343 and, 
1344 the sea inundated 2-3 km to the land. In 1509, the tsunami 
  
* Corresponding author. 
erstand the possible effects on those regions and should only be used for evacuation planning and reducing possible 
wave height was most probably more than 6 m above sea level. 
Sea inundated the area behind the city walls and invaded the 
streets. In 1766 the waves were recognised inner parts of the 
Bosphorus. In 1894 the sea receded up to 50 m and then 
returned. The wave height was less than 6 m. The bridges on 
the Golden Horn estuary were under the water. In 1912 the sea 
lifted a rowing-boat up to a height of 2.7 m at Yesilkóy. In the 
middle of the Strait of Istanbul, the waves demolished an 
anchored yacht. Finally in 1999 some abnormal events were 
observed around the Prince islands and in the Strait of Istanbul. 
2. MODELING FOR UNDERWATER FAILURES 
Numerical simulations are useful tools for analysing tsunami 
propagation and coastal amplification. The tsunami waves 
generated by earthquakes depend on the size and the impact of 
the source mechanism on the displaced water. On the other 
hand, those generated by underwater landslides are governed by 
the landslide geometry and its kinematics (Grilli and Watts, 
1999). 
By estimating different underwater landslide and earthquake 
scenarios in the Sea of Marmara, Yalciner et al. (2001; 2002) 
have modelled tsunamis. They proposed 3 different 
hypothetical tsunami scenarios; an underwater failure at 
offshore Yenikapi, another one offshore Tuzla, and an 
earthquake on the Armutlu Fault and two accompanying 
landslides located along this fault. These scenarios showed that 
the tsunami waves can reach the nearest coastal area within 5- 
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