USING LACUSTRINE SEDIMENTS TO RECORD PAST NATURAL HAZARDS: THE CASE OF ()

Laura Lamair* (1,5), Aurélia Hubert-Ferrari (1), Shinya Yamamoto (2), Masanobu Shishikura (6), Osamu Fujiwara (6), Evelien Boes (4), Stephen Obrochta (8), Atsunori Nakamura (6), Yosuke Miyairi (7), Yusuke Yokoyama (7), Marc De Batist (4), Vanessa M.A. Heyvaert (3,5), and the QuakeRecNankai Team (Ed Garrett, Helmut Brückner, Eisuke Ono, Svenja Riedesel, Koen De Rycker, Yoshiki Sato, Jan Walstra)

(1) Department of Geography, University of Liège, Belgium, (2) Research Institute, Yamanashi Prefectural Government, Yamanashi, Japan, (3) Department of Geology, Ghent University, Belgium, (4) Renard Centre of Marine Geology, Department of Geology, Ghent University, Belgium, (5) Geological Survey of Belgium, Royal Belgian Institute of Natural Sciences, Brussels, Belgium, (6) National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan, (7) University of , Atmosphere and Ocean Research Institute, Chiba, Japan (8) Akita University, Graduate School of Earth Resource Science, Akita, Japan

In this presentation, we will focus on the Fuji Five Lakes region. Since 2013, Mt. Fuji and the Fuji Five Lakes area (, Lake Shoji, Lake Sai, and ) are added on the world heritage list of UNESCO. Mt. Fuji is a main touristic attraction in Japan bringing each year 300 000 tourists. The Fuji Five Lakes are located at the foot of Mt. Fuji Volcano close to the triple junction where the North American Plate, the Eurasian plate and the Philippine Sea Plate meet. Therefore, the region can be impacted by Mt. Fuji volcanic eruption as well as by large magnitude earthquakes. Additionally, nearly every year, Japan is hit by strong winds, heavy rains with flood, landslides and high waves. These natural hazards may affect the Japanese economy by causing casualties and infrastructure damage. In the regions frequently affected by natural disasters like Japan, it is crucial to have a better knowledge of the recurrence times of such disasters in order to refine the probabilistic models. For that purpose, lacustrine sediments are often used. Lacustrine sediments retrieving by coring offer several advantages compared to onland drilling: the method is cheaper, the cores are easier to take and they have longer temporal span. Lacustrine sediments are generally good archives to record past natural hazards. However, each lake has its own particular setting and a different sensitivity to record paleohazards. Coupling geophysical data, sedimentological analysis and historical records is often required to identify natural paleohazards in the sedimentary records and to define the threshold sensitivity of the lake. Here, we will used Fuji Five Lakes as natural laboratory for the recording of paleohazards (typhoons, earthquakes and volcanic eruptions) and will discuss the sedimentary record of Lake Motosu, Lake Sai, Lake Yamanaka and Lake Kawaguchi over the last ca. 6000 years regarding their geomorphological characteristics.

*Corresponding author: [email protected]