On Monday,
the platform arrived from Hamana-ko to Kawaguchi-ko. At the end of the day, we
were ready to core. The aim of the survey is to get long cores from the Fuji
Five Lakes in order to retrieve the seismic history of the Nankai Through.
During this month, we will investigate Lake Kawaguchi, Lake Motosu and Lake
Sai. We will spend one week in Lake Kawaguchi and Lake Sai. Our best target is
the Lake Motosu where we will be for two weeks. This year, we decide to not investigate
Lake Yamanaka for several reasons. Lake Yamanaka is very close to Fuji volcano
and highly exposed to eruptions. The study of the 1998 old borehole revealed a
lot of scoria layers and we were not sure that our equipment could go through
them. Because our coring system was struck in Hoei scoria (1707A.D.), the age
of short cores taken last year is relatively well constrained. In 300 years,
Lake Yamanaka has not recorded any turbidites. This is why, this year, we will
focus on the other three lakes. In our long cores, we expect to find turbidites
triggered by earthquake that allow us to compare the earthquake fingerprint of each lake…
But first, we need to hammer!
The platform on Lake Kawaguchi
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