The "Giant Wave" hypothesis for the deposition of chaotic gravels high on the coastal slopes of the Hawaiian Islands remains controversial, in part due to the scarcity of detailed submarine information regarding the Alika debris-avalanche deposits. In order to interpret the Alika debris avalanches, a comprehensive submarine investigation using high-resolution bathymetric maps, ocean-floor observations and samples from submersibles, piston cores, and improved GLORIA side-scan images, was carried out. The sequence of debris-avalanche events is based on bathymetric investigations, draped sediments on megablocks in the South Kona slide area, and turbidites recovered by a piston core sampling 135 km southwest of the island of Hawaii (PC-13). The chemical compositions of the draped sediments and turbidite layers in the piston core are very similar, but differ from the matrix and block facies of the South Kona slide. These compositions suggest that the source for the turbidite layers was probably lava erupted subaerially from Mauna Loa. This geological evidence suggests that the Alika debris-avalanche deposits are unlikely to have formed in a single event or in rapid succession. They can be redefined as three geologically separated landslide events: the Kealakekua rotational slump, the Alika 1 debris avalanche, and the Alika 2 debris avalanche. The Kealakekua rotational slump probably occurred after the South Kona slide complex and before the Alika debris avalanches and was emplaced slowly. The Alika 1 and 2 debris-avalanche deposits can be divided into subfacies: (1) the main body of the debris-avalanche deposits (Alika 1d and 2d), (2) megaturbidites (Alika 1t and 2t) accompanying the debris avalanches, and (3) levee-overflow sediments (Alika 2s) derived from the suspension and reworking of Alika 2d. Thus, complicated bathymetric characteristics in the Alika debris avalanche deposits can be interpreted as an overlapping of multiple slope failures. Therefore, the newly estimated volumes of the landslide deposits, their boundaries delineated by high-resolution digital elevation models, are smaller than those of previous estimations.

The albedo of the ocean surface is of primary importance in the radiative energy balance of the Earth. It takes the smallest value of close to 0 over ocean water and the largest value of nearly 1 over snow-covered sea ice. The albedo of ocean water is determined by of the solar zenith angle, slope of the surface and optical properties of the atmosphere and ocean. The albedo of sea ice is significantly influenced by snow cover. During the warm season, ponds of melt water of snow and ice result in large reduction of albedo. Based on the knowledge from foregoing observational and modelling studies, the treatment of the ocean surface albedo in AFES (atmospheric general circulation model for the Earth Simulator) has been improved. Recent modifications to albedo parametrizations incorporated in AFES are described and optimum values for various parameters are adjusted to the observation data. The effects of albedo on global energy balance and atmospheric circulation are discussed.

During the R/V Natsushima NT07-07 cruise, magnetic and bathymetric surveys of the Suiyo Cross-Chain were conducted. The newly collected bathymetric data fill gaps of swath coverage of previous cruises in shallow depths, therefore, a complete data set of swath bathymetry is obtained. The West Suiyo Volcanic Complex (WSVC) is magnetized in totality positive, and has more complex distribution of the magnetization intensities and/or directions. The Suiyo Volcano (SV) is strongly magnetized. The magnetization intensities increase from the WSVC through the Suiyo Volcanic Ridge to the SV, i.e. from back-arc to volcanic front. It may indicate the SV mainly consists of younger basaltic rocks, while the WSVC consists of more differentiated rocks and/or is older. The western flank of SV is magnetized in positive, in contrast, the eastern flank may be magnetized in negative. Otherwise, the SV is interpreted as the magnetization of eastward declination. The deflection of the magnetic declination can be explained by the clockwise rotation of the seamount together with the Philippine Sea Plate. In the vicinity of the caldera of the SV has low or reverse magnetization. Low magnetization is likely due to hydrothermal activity in the caldera.

We carried out a wide-angle reflection and refraction experiment using 100 ocean bottom seismographs on a 536-km long seismic line crossing the southern Izu-Ogasawara Arc, and a multi-channel seismic reflection profiling of 204-channel hydrophone streamer on a 318-km long seismic line transecting from the Ogasawara Trough to the Ogasawara Plateau. The cruise was conducted by R/V Kairei of Japan Agency for Marine-Earth Science and Technology from March 4 to 30, 2007. The objectives of the cruise are to reveal the crustal structure of the southern Izu-Ogasawara Arc and detailed shallow structure of the Ogasawara Plateau and to understand the continental crustal formation and the collision style of oceanic plateau against to the subduction zone. In this paper, we summarize the seismic experiments and show the acquired data of ocean bottom seismographs and multi-channel seismic survey.