Angle of energy flux at the origin of two major tsunamis

The energy flux of the Japan Sea Tsunami of May 26, 1983 radiated offshore causing the destruction of ships in Shimane Prefecture, the fourth worst area hit. In 1960, a tsunami from Chile attacked the Pacific coast from the Ryukyu Islands to Adak Island Alaska. The energy flux of the latter was similar to that of the former. The angle formed at the origin off the Chilean coast by the energy flux was 68°48 or possibly slightly larger. The coincidence between the angle given by this process and that by the directivity theory of Miyoshi (1977) is good. The Sanriku District is located approximately on the center line of this angle. Judging from the fact that the Sanriku District was attacked most severely in 1960, it can be suspected that the energy flux was a little more sharply directed than estimated by the theory. The equivalent angle in the case of the Japan Sea Tsunami, which attacked the area from the tip of the Noto Peninsula to the east coast of the Korean Peninsula, was only 45°30 and the smaller angle can be explained as a refraction effect of the Yamato Bank. The above information should be useful for warnings of future tsunamis.     

True run-up heights reached by the huge tsunami of 1896

The run-up height reached by the tsunami of 1896 at the former Ryohri Village had been erroneously recognized as high as only 21.9 m. Our study (1983) renewed the figure of 38.2 m (Matsuo, 1933), which is now officially recognized.In 1980, we selected the spot, Raga, Tanohata Village, and, using a hand level, pointed out the decisive underestimation of the run-up height in Igi's report (1897). Our study, however, provided only circumstantial evidence that the maximum runup at the former Ryohri Village might be 38.2 m. In 1986, we directly studied the run-up height at the saddle point at Ohkubo, the former Ryohri Village using hand levels, and confirmed that it was at least as high as 36 m. Countermeasures for future tsunamis need major revisions, a part of which is the consideration on the combination of the large V-shaped Ryohri Bay and a neighboring small (V+U)-shaped bay. This consideration becomes essential and we show that the (V+U)-shaped bay is of the worst shape, basing on the survival ratios of individual small subhamlets, which have been recently ready for use (Yamashita, 1982).     

Problems concerning the Directivity of Tsunami

If knowledge of our theories on the directivity of tsunamis had received worldwide attention, the following operations could have been carried out internationally just after the large earthquake of 19 September 1985 which occurred near Acapulco, Mexico. Having found the great circle, “line S” which is perpendicular to the coast around Acapulco, we could have calculated the angles between line S and line A and between line S and line D, where line A and line D are the great circle connecting Acapulco and Auckland, New Zealand and that connecting Acapulco and Duke of York Island (Chile), respectively. The resultant angles are 30?43′ and 41?49′(>68?48′/2), we could thereafter neglect the eastern half of the offshore energy flux. When we assume that the speed of trans-Pacific tsunami is 400 knots, the probability that the actual tsunami will come earlier than the calculated arrival time proves to be $$\frac{1}{{\sqrt {2\pi } }}\int_{ - {\text{ }}\infty }^{ - {\text{ }}0.689} {e^{ - t^{{2 \mathord{\left/ {\vphantom {2 2}} \right. \kern-\nulldelimiterspace} 2}} } dt = 0.2454} $$ Contact with New Zealand prior to the forecasted arrival time was essential, but the tsunami attention for the Japanese coast was unnecessary. Without such application of our directivity theories, frequent fruitless warnings will be issued for future trans-Pacific tsunamis. Quick improvements in warning procedures are required.     

X-ray observation of AGN's from TENMA

In order to investigate the structure and mechanism of active galactic nuclei through X-ray observation, detailed energy spectra are examined with the gas scintillation proportional counters on board TENMA. For three selected objects, PKS 2155-304, Centaurus A and IC 4329 A, the observational results in the intensity variation, the spectral shapes and the iron line features are presented.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.     

LORA: a local ensemble transform Kalman filter-based ocean research analysis

Ocean Dynamics - We have produced an eddy-resolving local ensemble transform Kalman filter (LETKF)-based ocean research analysis (LORA) for the western North Pacific (WNP) and Maritime Continent...     

Degradation of outer membrane proteins of <Emphasis Type="Italic">Synechococcus</Emphasis> sp. <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in situ</Emphasis>

To examine the possibility that outer membrane proteins (OMP) of Synechococcus sp. remain in seawater, we investigated the stability of OMPs in vitro and in situ. Some fractions prepared from Synechococcus sp. CSIRO-94 were treated with trypsin and proteinase K. Four tightly bound OMPs were separated from Synechococcus. We designated the two major OMPs of 52 kDa and 48 kDa as Omp52Sy and Omp48Sy, respectively. Degradation of the OMP in natural seawater was monitored in microcosms to which intact Synechococcus cells and outer membrane (OM) were added. Omp52Sy and Omp48Sy were the most stable against trypsin and proteinase K among the OMPs when they were embedded in the OM. However, in the microcosm experiment using intact cells, Omp52Sy and Omp48Sy were detected in the particulate fraction only during the first 4 days, after which they could not longer be detected. Omp52Sy and Omp48Sy were the most stable proteins among the Synechococcus OMPs in vitro, but they might be degraded in situ. This indicates that stability of Synechococcus porin differs depending on complex formation with other membrane molecules, which might cause different preservation of microbial membrane proteins in the dissolved protein pool in the ocean. This study suggests that Gram negative bacterial OM with thin peptidoglycan forms a lipid bilayer that proptects OMP, but Synechococcus OM with thick peptidoglycan cannot form a lipid bilayer. The incomplete bilayer might not be able to protect from protease attack in the natural environment.     

Suzaku observations of charge exchange emission from solar system objects

Recent results of charge exchange emission from solar system objects observed with the Japanese Suzaku satellite are reviewed. Suzaku is of great importance to investigate diffuse X‐ray emission like the charge exchange from planetary exospheres and comets. The Suzaku studies of Earth's exosphere, Martian exosphere, Jupiter's aurorae, and comets are overviewed (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)