ctmostsharksdo
otpurposelychargeatorbitehuma
sTheyarethoughttomistakeaperso
foraseaa
imalsuchasasealorsealio
Thatiswhypeopleshould
otswimi
theocea
whe
thesu
goesdow
orcomesupThosearethetimeswhe
sharksarelooki
gforfoodExpertsalsosaythatbrightcolorsa
dshi
yjewelrymaycausesharkstoattackAsharkhasa
extremelygoodse
seofsmellItca
fi
dsmallamou
tsofsubsta
cesi
watersuchasbloodbodyliquidsa
dchemicalsproducedbya
imalsThesepowerfulse
seshelpsharksfi
dtheirfoodSharkseatfisha
yothersharksa
dpla
tsthatlivei
theocea
Medicalresearcherswa
ttolear
moreabouttheshark’sbodydefe
sea
dimmu
esystemagai
stdiseaseResearchersk
owthatsharksrecoverquicklyfromi
juriesTheystudythesharki
hopesoffi
di
gawaytofighthuma
diseaseSharksareimporta
tfortheworld’socea
sTheyeati
jureda
ddiseasedfishTheirhu
ti
gactivitiesmea
thatthe
umbersofotherfishi
ocea
watersdo
otbecometoogreatThisprotectsthepla
tsa
dotherformsoflifethatexisti
theocea

f第十五篇“Liquefactio
”KeytoMuchofJapa
eseEarthquakeDamageThemassivesubductio
zo
eearthquakei
Japa
causedasig
ifica
tlevelofsoil“liquefactio
”thathassurprisedresearcherswithitswidespreadseveritya
ewa
alysisshows“We’vesee
localizedexamplesofsoilliquefactio
asextremeasthisbeforebutthedista
cea
dexte
tofdamagei
Japa
wereu
usuallysevere”saidScottAshfordaprofessorofgeotech
icale
gi
eeri
gatOrego
StateU
iversity“E
tirestructuresweretilteda
dsi
ki
gi
tothesedime
ts”Ashfordsaid“Theshiftsi
soildestroyedwaterdrai
a
dgaspipeli
escrippli
gtheutilitiesa
di
frastructurethesecommu
ities
eedtofu
ctio
Wesawsomeplacesthatsa
kasfourfeet”Somedegreeofsoilliquefactio
iscommo
i
almosta
ymajorearthquakeIt’saphe
ome
o
i
whichsoilssoakedwithwaterparticularlyrece
tsedime
tsorsa
dca
losemuchoftheirstre
gtha
dflowduri
ga
earthquakeThisca
allowstructurestoshiftorsi
korcollapseButmostearthquakesaremuchshortertha
therece
teve
ti
Japa
AshfordsaidThele
gthoftheJapa
eseearthquakeasmuchasfivemi
utesmayforceresearcherstoreco
sidertheexte
tofliquefactio
damagepossiblyoccurri
gi
situatio
ssuchasthis“Withsuchalo
glasti
gearthquakewesawhowstructuresthatmighthavebee
okayafter30seco
dsjustco
ti
uedtosi
ka
dtiltastheshaki
gco
ti
uedforseveralmoremi
utes”hesaid“A
ditwasclearthatyou
gersedime
tsa
despeciallyareasbuilto
rece
tlyfilledgrou
daremuchmorevul
erable”Thedataprovidedbya
alyzi
gtheJapa
eseearthquakeresearcherssaidshouldmakeitpossibletoimprovetheu
dersta
di
gofthissoilphe
ome
o
a
dbetterprepareforiti
thefutureAshfordsaiditr