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Lecture

Lecture5d.pdf


Department
Archaeology
Course Code
ARH306Y1
Professor
All

Page:
of 2
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Deformation!and!slip!during!March!11!2011!Earthquake!
Uplift!and!subsidence!of!ocean!floor!
Eastward!movement!of!Japan!
Just!off!Tokyo,!the!outer!margin!of!the!continent!rose!(7m)!in!an!instant!
o The!inner!coast!went!down!
o Whole!ocean!floor!off!of!Japan!was!tilted!back!down!towards!the!land!
Japan!was!raised!up!to!accommodate!the!pacific!plate!slipping!down!beneath!
it!
All!the!sea!defenses!were!dropped!
o Water!was!literally!running!downhill!
o Wave!exceed!height!of!coastal!protection!
Japan!moved!25!meters!to!the!east!
o Representation!of!death!of!pacific!ocean!
o Happens!every!major!earthquake!
In!1896,!there!was!a!tsunami!that!killed!22!000!people!
o Did!not!even!get!reported!because!it!was!a!commonplace!event!
Frequency!of!eruptions!and!earthquakes!isn’t!increasing;!but!the!populations!
of!major!cities!are!
o This!is!what!makes!them!more!dangerous!
!
!
Mount!Fuji!and!the!city!of!Fujioshida!
Hasn’t!had!an!eruption!in!700!years!
o From!profile!does!not!look!dangerous;!almost!like!a!shield!volcano!
However!research!shows!it!is!actually!dangerous!
o Has!history!of!pyroclastic!flows!
Shinto!temple!right!below!the!volcano!
Every!august!a!replica!of!the!volcano!is!paraded!through!the!city!
o Said!to!be!a!goddess!inside!it!
o If!she!likes!what!she!sees!(inhabitants!have!been!good!people),!she!
will!stop!the!volcano!from!erupting!
In!the!evening!they!light!pyres!mimicking!the!volcano!
o People’s!ancestors!are!supposed!to!come!out!
!
How!many!eruptions?!How!frequent?!
Outcrop!of!sediments!exposed!
Each!dark!band!is!one!pyroclastic!flow!(one!eruption)!
Black!spots!are!burnt!tree!trunks!
o Forests!were!knocked!down!and!burnt!
o Dated!accurately!
Based!on!frequency,!mount!Fuji!seems!to!be!a!dangerous!volcano!
o Inhabitants!are!lucky!
!