Effects of Climate Change on Natural Disasters at Coastal Zones Kazuya Yasuhara, Ph D Professor Ibaraki University, Department of Urban &Civil Engineering, 4-12-1 Nakanarusawa-cho, Hitachi-city, Ibaraki, 316-8511, Japan. E-mail: [email protected], Fax: ≁81-294-38-5268, Phone:≁81-294-38-5166
22
Embed
Effects of Climate Change on Natural Disasters at Coastal …2009/11/16 · Effects of Climate Change on Natural Disasters at Coastal Zones Kazuya Yasuhara, Ph D Professor Ibaraki
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Effects of Climate Change on Natural Disasters at Coastal Zones
Kazuya Yasuhara, Ph DProfessor
Ibaraki University, Department of Urban &Civil Engineering,
Change in inundation area Change in inundation area in the Pacific coastin the Pacific coast
-20 0 20 40 60 80 100
海面上昇(cm)
0
20,000
40,000
60,000
80,000
100,000
120,000
浸水
面積
(ha)
0.7 1 1.3 1.6高潮増大率
0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7
高潮増大率
0
20,000
40,000
60,000
80,000
100,000
120,000
浸水
面積
(ha)
-20 0 20 40 60 80 100海面上昇 (cm)
(a) Influence of SLR (b) Influence of SSIR
Inundation area is sensitive to SLR.
Change in economical loss caused by storm Change in economical loss caused by storm surge in the Pacific coastsurge in the Pacific coast
-20 0 20 40 60 80 100
海面上昇(cm)
0
10
20
30
40
50
60
70
被害
額(T
\)
0.7 1 1.3 1.6高潮増大率
0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7
高潮増大率
0
10
20
30
40
50
60
70
被害
額(T
\)
-20 0 20 40 60 80 100海面上昇 (cm)
(a) Influence of SLR (b) Influence of SSIR
Inundation damage cost is also sensitive to SLR.
Liquefaction
(Great Hanshin Earthquake, 1995, Japan)
Recent situation of rainfall in Japan (after JMA, 2006)
0
1
2
3
1976 1981 1986 1991 1996 2001 2006
Appearance counts per year of which amount of precipitation per day
is larger than 400mm
Appe
aran
ce c
ount
s pe
r yea
r(A
t 100
obs
erva
tion
poin
t)
Year
Average in 1976-19860.5
Average in 1987-19960.4
Average in 1997-20061.2
0
5
10
15
20
25
30
35
1976 1981 1986 1991 1996 2001 2006
Increasingtendency
Num
ber
of
appea
rances
(At
100
obs
erv
atio
n po
ints
)Year
1976-1986 average16.0times/100point
1986-1996 average17.7times/100point
1996-2006 average23.2times/100point
(a)Appearance counts per year larger than 400mm in Japan
(b) Number of appearance larger than 50mm in Japan
(a) Variations of occurrence frequency of earthquake with 5 strong seismic intensity
Occ
urre
nce
freq
uenc
yO
ccur
renc
e fr
eque
ncy
(b) Variations of occurrence frequency of earthquake with 6 weak seismic intensityYear
Year
Occurrence frequency of recent earthquakes in Japan(arranged using data from JMA, 2006)
PurposePurposeVulnerability to
liquefaction hazards in theobjective region has beenassessed throughcomparison of GIS-aidedliquefaction hazard mapsbefore and after SLR andclimate change caused byglobal warming.
Tokyo Bay
Tokyo Bay
Objective area
Economical loss for eastern lowland of TokyoEconomical loss for eastern lowland of Tokyo
Objective area: coastal area in the eastern part of Tokyo
・Collection of ground data・Ground modeling・Estimation of rise in GWL caused by climate change and SLR ・Estimation of economic loss
Distribution of liquefaction hazard
(a) Scenario I (present situation)
(b) Scenario II(consideration of SLR in 2100)
(c) Scenario III(consideration of rainfall from 2081 to 2100)
(d) Scenario IIV(both SLR and rainfall from 2081 to 2100)
Liquefaction resistance factor, FL
Evaluation of possible liquefaction through depth in an objectivEvaluation of possible liquefaction through depth in an objective e location using the method proposed by Iwasaki et al.(1996)location using the method proposed by Iwasaki et al.(1996)
Bor
ing
log
Bor
ing
logzz
00hh
∫=20
0)()( dzzwzFPLFL
FL
FL
FL
FL
FL
FL
FL
Integration of the liquefaction
potential through depth, using this
equation..
⎩⎨⎧
>≤−
=1011
)(L
LL
FFF
zF
zzw 5.00.10)( −=
(a) Scenario I(present situation)
(b) Scenario II (consideration of SLR in 2100)
(c) Scenario III (consideration of rainfall from 2081 to 2100)
Distribution of economical damage caused by earthquake
(d) Scenario IV (both SLR and rainfall from 2081 to 2100)
Increase in economic damage from the present situation to the scenario IV
Economical loss induced by liquefaction is4 thousand billion Yen approximately in the case of both SLR and heavy rainfall considered.
Liquefaction damage has appeared rather in land than along the coast.
Possible adaptation to natural disasters at coastal zonesAdaptation
Protection Accommodation Evacuation
Storm surge & River flood
Additional bankingWater protection workEarly warning system and evacuation systemConstruction of shelter
Hazard mapAppropriate land use Regulation of land usein hazardous areaInsurance
Restriction of developmentEvacuation from dangerous areaPublic support for evacuation
Lique- faction
Monitoring of GWLLowering of GWLAdditional bankingSoil improvement and reinforcement
Hazard mapAppropriate land use Regulation of land usein hazardous areaInsurance
Restriction of land useEvacuation from dangerous areaPublic support for evacuation
Slope failure
Protective pileEarly warning system and evacuation system
Hazard mapRisk map Regulation of land usein hazardous areaInsurance
Restriction of land useEvacuation from dangerous areaPublic support for evacuation
Conclusion1) Sea level rise and buildup of high tides triggered by global warming expand the flooding area and population. As global warming progresses, reclaimed lands developed long ago will face a high risk of flooding by high tides in the inner parts of the three large bays.
2) Sea level rise and anomalous rainfall raise the groundwater level and expand areas that suffer geotechnical hazards through liquefaction in the event of an earthquake.
3) The procedures for estimating economical loss induced by storm surge and liquefaction are presented. The results should be put to good account for proposal of the appropriate adaptation.