International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004
Lake vicinity and south coast of izmit Bay are the areas of Vectors obtained form Esme measurements show a displacement
interest in the project. implies especially with faulting in the east and southeast direction.
EA Obtained vectors from the west corner of Sapanca Lake do not
The permanent ground deformations were measured through the show a unique direction. There is a similar movement with that of
aerlal photogrammetry technique at several sites within the Esme in the north of the model, while sparse movement in the
earthquake region. The three-dimensional coordinates of the south of model because of varying soil structure and locating fault.
common points on pre- and post- earthquake photographs were And vectors in the area of Sapanca Otel have directions mainly to
determined, and the differences between them are interpreted as north, upward the Lake because of the liquefaction (Figure 2). To
the liquefaction and faulting induced displacements (Aksu et al., explain the results better, detailed measurements have been made
2002). at coastline area of first measurement regions too.
2. MEASUREMENTS
Geodetic surveying activities were carried out and aerial
photographs were taken in 1:16.000 scales covering the areas
Avcilar, Yalova, izmit, Adapazari by General Command of
Mapping on September 8", 1999 after the Marmara earthquake.
dhese It is ideal to use aerial photographs pertaining to pre- and post-
process situation of earthquake in large scales (such as 1:5.000,
tions in 1:10.000) for determination of liquefaction and faulting. But
because of not having triangulation points of 1:16.000 scaled
e used, photos taken in 1970, 1:35.000 scaled aerial photographs taken
in 1994 were to be used instead. Although it seems a
1ced by disadvantage to use small scale photographs, temporal
easured resolution that is closest dates for the pre- and post-situation
rya city aerial photographs is especially preferred in the areas like
1rement Marmara region which have dense new structuring.
ova.
ographs Digital aerial triangulation measurements and block adjustments
ne were were implemented using scanned aerial photographs in 21
ommon 1 m. Root mean square error of 6-8 4/ m. obtained from this
between process is normally acceptable for topographic mapping in
GCM. As many and well-distributed common points as possible
have been selected on the aerial photographs for coordinate
measurements. These points are on the features where artificial
ges and displacements are minimum, such as junction of roads, bridges Figure 2. Displacement vectors around the Sapanca Hotel
structure and buildings (Atak et al., 2003). After obtaining the horizontal
ier aun and vertical displacements, images and displacement vectors Second phase measurements were also implemented in eight
a were merged and so the results could be interpreted (Hamada, different areas on the coastline of Izmit Bay in addition to
1992). Sapanca Lake. Obtained results can be seen in Table II.
gual First, cartesian coordinates have been measured in the IZMIT BAY RESULTANT VECTOR
ét photogrammetric models of Sapanca Lake vicinity. Movement <(POST-PRE)(1999-1994)>
m almost ves have been calculated by eem Of ns ses AREA Point DE DN DL DV
she past 0 e common points. Resu $ about the Sapanca Lake NAME | Number (m) (m) (m) (m)
dic not measurements can be seen in Table I.
rE BASISKELE
Eme SAPANCA RESULTANT VECTOR Mean | 48 -1.389 | -1.482 | 2.766 | 1.021
emt LAKE <(POST-PRE)(1999-1994)> N
G Ofen AREA (Point | DE | DN | DL | DV SEGME
too, the NAME Number‘! (m) (m) (m) (m) Mean | 147 -1.064 | -1.146 | 2.317 | -0.132
kes (like = GOLCUK :
of more Oi Meam | 92 -1.580 | -1.259 | 2.440 | -2481
faction) Mean 1 418 0.410 | 0.835| 1.460; -1.714 DECIRMENDERE
serves a Mean | 132 -1.354 | -1.215 | 2.445 | -0.602
by both on 2 219 0.4671 1.207] 1.778 | -2.041 HALIDERE
et € DIVE > “12 i
dis Mean | 305 [2351] -0428]| 2660] 0.617 Men A 6 L278 1 0385 | 2.058 | -1.454 |
e 2.575| 0.193| 2.849| 0.762 5 T
: ven. © P 122 Mean | 71 -0.438 | 0.354 | 1.399 | -0.680 i
azar! an à |
measure Mean 1 423 0.608 | 0.291 | 3.036; 0.602 EA 145 2.069 | 1.112 | 2.881 | -1.505 l
d faulting Mean 2 50 1.304 | 0.764] 2.245} 0.131 YALOVA li
General Mean 2-Detailed Measurements Mean | 301 1.637 | 0.709 | 2.155 | 1.037 I
, Sapanca l
Table 1. Sapanca Lake area measurements and results
649
Table 2. izmit Bay measurements and results