TokyoTakesiba is about 108.6km away from here in a straight line.
An active volcanic island in the Pacific Ocean Sagami Bay on the Philippine Sea plate.
13km north-northwest south-southeast 9km ENE-WSW
Island cover an area of 91.06k㎡
Households 4,806 Population 8,194(2015/08/01)
Latitude 34°43′29″ Longitude139°23′41″
Basaltic volcano- Silicon dioxide content 51-53wt%
Style of eruption - scoria→lava flow→volcanic ash
Recent eruption of Mt. Mihara
1986.11.15 17:25 (summit A crater)
1986.11.21 16:15 (frank eruption B1～B8 crater)
1986.11.21. 17:47(frank eruption C1～C11crater)
C6 lava flow was imminent in Motomati in oshima→seek shelter off the island for one mouth.
「Itadori虎杖in japanese」 Japanese knotweed - Fallopia japonica
pioneer plant after eruption
wrechage of plane was sighted on the lip of the cardera of Mt. Mihara
go down to the collapse caldera floor. this cardera was made 1700-1750 years ago. Member S2 アンドラーシュ ワグナーさん(ハンガリー 30歳) 後ろはパパ
アンタル・ワグナーさん(ハンガリー 63歳 地質学専攻の理学博士)
「Sennburi」-Swertia japonica Makino
Decoction of bowel medicine
「Ashitaba」 of as a vegetableー Angelica Keiskei
「Nannban kiseru」 Aeginetia indica L
leafless parasitic plant of the Japanese pampas grass
「Akadare」 red gully - iron content included in the magma touched atmospheric oxygen and was oxidized.
scoria corn of 8th centuries - lava wall-aa lava (1778.11.06)in the An'ei era during the Edo period.
An'ei large-scale eruption(1777.08.31-1792) Member Y1
they are climbing Mt.Mihara,summit A crater.
take a souvenir picture in front of summit A crater
for the first time in 565 years
Andesitic eruption - silicon dioxide content 53.5 -67wt%
Main magma reservoir depth 9km →summit crater(basaltic magma)
Vice-magma reservoir depth 4-5km →frank eruption B1-B8crater(andesitic magma)
Frank eruption mouth just after the 1986 year eruption.
Quotes from Motomaro Sirawo's picture
If it is fine, you see Japan's highest Mount Fuji.
「URASABAKU」 this slope turned into desert on the way of the strong prevailing wind. southwest wind , northeast wind
Even if a seed is implanted, it is spurted and wind cannot germinate.
Geological cut surface
formation N4←S2←O1←O2←............←O95 N4(750) S2(300) O95(15,000-19,700BP)
a strata - tree layer ー lower- Scoria, middle- Ash, upper- Aeolian deposit(air-fall deposits)
the incommensurate stratum is a thing caused by the erosion.
You arrived at the Okada Port five minutes before a start on a voyage.
It was a busy guide,but how about the geo-site of Izu-Oshima is
Please take care. Let's meet again sometime.
Quotes from Dr.Tsukui
Quotes from papers in Meteorology and Geophysics