Summary
ThisisKantoacomprehensive

Regionreport，conducted

titled

from

Study

on

stressfieldandforecast

fisca11994to1998by

theSeismology

ofseismicandactivityinV61canology

theResearch

Department，MRI，asaspecialresearchproject．Thisstudyconsistsofthreesubjects，
1）The

objective

evaluation

andforecastofseismicity，

2）Adataめaseforseismicprocesses

andcmstalactivities，and

3）Kinematicmodelingforestimatingcrustalactivities．
Theresults
Chaptertoarelevaluatesummarizedinthe

detailsaseismicity

detecting

on

also

before

found

a

most

activebevalidforthechangeimportanttopic

intheandforecastingtheearthquakechangeofoff

it

the

seismidty．Wbto

the

Kanto

east

coast

about10years，in
Kanto

areas

long−term

prediction

oflargeearthquakes

related

to

the

plate

offoreshocks，whichhaslongbeenisconsideredcharacteristics

to

be

Chiba

seismicity，ofseismicity

in

the

a

succeededsouth−west

thisIbarakibecauseincansuchfluctuation．The

akeyissue

inin1987characteristic

regionmotionmethodprefecture

region．This

in

adoptedregion，and

ofregular

seismicity

coversevaluating

quantitatively，applied

periodic

ofthe

periodicandchangeprefecture，one

consideredobjectively

objectively

seismicity（ハ4冒6．7）．We

studysixchaptersinthisreport．

aotherearthquake

prediction．Itisbeenwe11㎞o、mthatmanyearthquakesintheIzuregionhavebeenaccompaniedby
activeforeshocks．Byusingthe
methodtheoftheforeshocks，focusing

forecast

accompanied

originseismicitydatainthis

ofthe
byevents

foundthatthe

main

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shock

onin

foreshocks

theaintemporalvariation

developedandconcentration

probabilistic
theswams，foreshockspatialregion，we

Izu

temporalmanner．W6thenregion，and

activities

showedofforeshocklfrequency

anappliedclarifieddiscrimination

ofse圭smicity，andthismethod

tostudiedtheevents

in

most

cases

exceptvolcanic

quiescencejustbefore

the

main

events．W6also

canbe

that

empirical

appro》dmatedbythe

inversepowerlawoftime，bystackingmanyforeshockactivities．
Chapter2reports
process
from

to

the

results

effect，attenuation

theobserved

determineenabledthe

alongrecordtheof

byseismic

estimationstrongthegroundpropagation

inversion，andmomentand

some

motionobservations量npath，and

amplification

characteristics

faultparameters

ofsmallareearthquakes

sourceprocesses

ofearthquake，whichbothcausedsignificant

damagetodate．Inaddition，thetectonic

characteristics

takingtheplate

structure

Chapter4explains
installedtocollect

Chapter4also

mechanism

to

the

the

region．Source

site
also

fromthearedecomposeddeveloped

atool

seismogram，and

ofthoseparametersforeventswith1臨downto3．4．

thesurviving

near

Kanto

studied．Wb

Chapter3presents

seismograms

theandseismicityinto

seismic

seismic

explainsthe

data

databasesolutionsbyusingbroadband

theearthquake
Kanto

and

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region，estimatedfromofthose

discussed

eventsareoldaccount．

telemetry

waveform（1ata

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systemallviaoverJapan

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satellite．This

for

relevant

thestudiessystem．W6developed

amethodto

seismogramscollecte（1bythissystem．

tosystem

thisdetermine

wasproject．

earthquake

Chapter5discusses

theGPSand丘deand

Tokaiandcomparetheseismicresponses．W6also

found
that

gauge

recentregions

observation．、Wbwith

itwiththatthecrustalantheoriginal

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arate，and

ef蚕ectcanbe

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therepresentativecontinuousGPSobserva』tions

at

tide

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revealedvertical

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changeobservation

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Chapter6，theThis

chapter

final

reports

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consistent

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