The survey of Lake Kawaguchi is already done !

We finished the coring in Lake Kawaguchi, it was a real success!  Lake Kawaguchi is a shallow lake with a maximum depth of 12 m. It is characterized by three sub-basins – Western, central and East basins. We investigated two sites, one in the western basin and one in the central basin.

The Fuji Five Lake survey has started !

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

Every end is a new beginning

Our working days on coastal Lake Hamana are now definitively over. The platform has been relocated to the Fuji area, where coring operations on Lake Kawaguchi were started.  

Unfortunately, we did not succeed in retrieving all missing core sections on site 3 and site 4 of Lake Hamana, since very strong winds threw a spanner in the works and we were not able to sail out during the last two days. Nevertheless, we now possess sediment samples up to a depth of 9 m below the lake floor, from four different locations along a N-S transect throughout the central basin. Such transect allows us to map the extent and lateral variations of tsunami deposits, which will be traced by executing a series of sedimentological, geophysical and geochemical analyses.

But first… our cores have to be shipped back to Belgium. This will be done at the end of November, after the Fuji survey is finished as well.

Sneak peaks of Mount Fuji from Lake Hamana