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Sedimentation processes caused by a modern tsunami have been discussed from the point of view of geologic and numerical investigations of the 1992 Flores tsunami in Indonesia. Geologic evidence on Babi Island shows an invasion of two waves of different direction and magnitude, which resulted in widespread deposition of marine sand on the north and south-southwest shores. On the latter, coarse and well-sorted carbonate sand containing molluscan shells suggests that much more destructive waves swept across the southern coast, as compared with the northern coast, where the deposit included medium carbonate sand with a silty component. A physical explanation for such destructive waves on the southern coast of Babi is provided by a numerical simulation of the tsunami generation and propagation. The geologic and numerical results indicate that an isolated island surrounded by a circular shoreline or reef edge will be subject to the most destructive waves on the coast on the back side of the island relative to the tsunami source.

The Hellenic arc is a terrane of extensive Quaternary volcanism. One of the main centers of explosive eruptions is located on Thera (Santorini), and the eruption of the Thera volcano in late Minoan time (1600-1300 B.C.) is considered to have been the most significant Aegean explosive volcanism during the late Holocene. The last eruptive phase of Thera resulted in an enormous submarine caldera, which is believed to have produced tsunamis on a large scale. Evidence suggesting seawater inundation was found previously at some archaeological sites on the coast of Crete; however, the cause of the tsunami and its effects on the area have not been well understood. On the Aegean Sea coast of western Turkey (Didim and Fethye) and Crete (Gouves), we have found traces of tsunami deposits related to the Thera eruption. The sedimentological consequences and the hydraulics of a Thera-caused tsunami indicate that the eruption of Thera volcano was earlier than the previous estimates and the tsunami did not have disruptive influence on Minoan civilization. Keywords: Thera eruption, Thera tephra, Minoan tsunami, tsunami propagation, tsunami deposits.

Understanding of the mechanism of the East Asian Summer Monsoon (EASM) is required for the prediction of climate change in East Asia in a scenario of modern global warming. In this study, we present high-resolution climate records from peat sediments in Northeast Japan to reconstruct the EASM variability based on peat bulk cellulose δ13C since the last deglaciation. We used a 8.8m long peat sediment core collected from the Tashiro Bog, Northeast Japan. Based on 42 14C measurements, the core bottom reaches ~15.5 ka. δ13C, accumulation rate and accumulation flux time-series correlate well to Greenland ice core δ18O variability, suggesting that the climate record in Northeast Japan is linked to global climate changes. The δ13C record at Tashiro Bog and other paleo-EASM records at Northeast and Southern China consistently demonstrate that hydrological environments were spatially different in mid-high and mid-low latitude regions over the last 15.5 kyr. During global cooling (warming) periods, mid-high and mid-low latitude regions were characterized by wet (dry) and dry (wet) environments, respectively. We suggest that these climatic patterns are related to the migration of the EASM-related rain belt during global climate changes, as a consequence of variations in intensity and location of both the Intertropical Convergence Zone (ITCZ) and the Western Pacific Subtropical High (STH). The location of the rain belt largely influences the East Asian hydrological environment. Our δ13C time-series are characterized by a 1230 yr throughout the Holocene and a 680 yr periodicity during the early Holocene. The 1230 yr periodicity is in agreement with North Atlantic ice-rafted debris (IRD) events, suggesting a teleconnection between the Northeast Japan and the North Atlantic during the Holocene. In addition, it is the first evidence that the Bond events were recorded in terrestrial sediment in Japan. On the other hand, the 680 yr periodicity between 10.0 and 8.0 kyr is consistent with a prominent 649 yr solar activity cycle, suggesting that solar activity affected EASM precipitation during the Hypsithermal, when orbital-scale solar insolation was at a maximum in the Northern Hemisphere. [ABSTRACT FROM AUTHOR]

Knowledge of the evolution of arboreal forests is necessary to interpret the cause of climate formation in intracontinental regions. Paleoproxy records of sediment cores from Lake Hovsgol, Mongolia show that watershed conditions have fluctuated widely during the last 30 ka because of changing orbital parameters. Termination of glacial cooling and the subsequent prevalence of deglacial warming were consequences of solar forcing. Arboreal forests exerted an important influence on the atmospheric moisture cycle at high latitudes. Air pressure decreased because of raised humidity from water vapor penetration into inland regions that occurred along with summer monsoons. Data showing utilization of solar energy are necessary for establishing climate conditions. Atmospheric warming under increased insolation caused a shift of the monsoon limit to the north, amplifying the summer moisture supply to the watershed. That amplification engendered the appearance of the maximum vegetation in the Hovsgol drainage basin at the beginning of the Holocene. The retreat of arboreal forests that occurred along with decreased solar energy shrank the humidification-vegetation feedback loop, thereby decreasing the atmospheric humidity. The consequently lowered vapor pressure contributed to the incursion of cool air masses from the north. [ABSTRACT FROM AUTHOR]