| XXXIX-B8, 2012
Legend
ÿ Tsunami damage
level
z Rank
Rank2
Rank3
0 250 500 1,000 m
LLL EL LLL
y f Sendai Plain
ded depth by MMS
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B8, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
3. RESULTS OF OVERLAY ANALYSIS
3.1 Relationship between tsunami damage and tsunami
depth
Figure 4 and 5 show overlay maps of tsunami damage level
and tsunami flooded depth measured by MMS at Yuriage area,
Natori City, Miyagi Prefecture and at the Sendai Airport area,
Iwanuma City, Miyagi Prefecture, respectirely.
These figures show that the area with over 4m tsunami
flooded depth is equivalent to the rank 1, and the area with over
1.5m tsunami flooded depth is equivalent to rank 2.
Figure 6 shows the distribution of tsunami flooded height
measured by field survey results of the 2011 Tohoku
Earthquake Tsunami Joint Survey Group (2011) and the
authors’ field survey and by MMS of GSI. Tsunami flooded
height is calculated by the following formulas: Tsunami flooded
height = tsunami flooded depth + LiDAR DEM. The
measurement results by MMS correspond well with the
measurement results by field survey.
Ke
8: Me ar ıng pol
(Ualtmt
Sd Tr tram (Damage kuel:
Rank1
i Hi. SS i Ns LESS SSS Vi S i, 2 ite
Figure 4. Tsunami flooded depth measured by MMS at Yuriage
area (base map is Cyber Japan Web System)
s E S .
S Se OST
du TTT
Figure 5. Tsunami flooded depth measured by MMS at Sendai
Airport area
SU
3.2 Relationship between tsunami damage and geographic
condition such as landform, elevation and land use
The results of overlay analysis about geographic information
and tsunami damage categories are shown in figure 7, 8, 9.
Figure7 is overlay map of tsunami damage and landform
classification. Figure8 is overlay map of tsunami damage and
DEMs. Figure9 is overlay map of tsunami damage and land use.
In this section, we describe the outline of landform and land
use in Sendai Plain using figure 7 and figure 9.
Landform within 1 km area from the coastline is mainly sand
dune or sand bar with little higher elevation. Wide sand bars are
dominate in the northern area from Abukuma River, but several
narrow sand bars are dominate in the southern area from
Abukuma River. Landform of inland area over lkm from the
coastline is coastal plain or delta. Valley plain or flood plain is
dominated along Nanakita River, Natori River and Abukuma
River. Natural levee and former river bed are only dominant
along main large rivers.
Land use on sand dune or sand bar is forest, other farmland
and building area. Forest is dominant in the northern area from
Abukuma River, however, other farmland is dominant in the
southern area from Abukuma River. Land use of inland area
over 1km from coastline is mainly paddy field. As building area
and other farmland in inland area have zonal distribution along
the coastline, these land use located on sand dune or sand bar in
inland area.
The results of overlay analysis between tsunami damage level
and other geographic information are as follows:
1) The completely destroyed area (Rank 1) was located
within 1km area from the coastline. Flooded depth of
this area is over 4m, and landform classification of this
area is almost sand dune or sand bar which has a little
higher elevation compared with other area (Figure 7, 8).
Contrary to a poor relationship between tsunami damage
and landform condition such as landform classification
or elevation, there is a good relationship between area of
tsunami damage rank 1 and distance from coastline.
Legend
Flooded height
by field survey (m?
9
9 2-4
e —
®
@® --
Flooded height
by MMS (m)
Flooded height by
Joint Survey Group(m
0-1
1-2
2-3
3-4
4-5
e
e
@
e
e 5-6
©
#The 2011 Tohoku Earthquake
Tsunomi Joint Survey Group
| Tsunami damage rank
Tsunami damage rank2
Elevation (m)
20
Figure 6. Distribution of tsunami flooded height measured by
MMS and other research group
