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Volume 52 (2013)
- Issue 6 Pages 241-
- Issue 5 Pages 191-
- Issue 4 Pages 95-
- Issue 3 Pages 53-
- Issue 2 Pages 33-
- Issue 1 Pages 1-
Volume 52, Issue 5
Displaying 1-4 of 4 articles from this issue
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The Paper for the 2011 Japan Association for Quaternary Research Academic Award
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Akira Sangawa2013 Volume 52 Issue 5 Pages 191-202
Published: October 01, 2013
Released on J-STAGE: August 10, 2014
JOURNAL FREE ACCESSIn Japanese archaeology, date sequencing for remains and artifacts has been studied thoroughly, so when an earthquake trace is found in an archaeological excavation, the approximate date of the earthquake can be identified. When the earthquake traces are confirmed by temple records and diaries, the precise date of this trace becomes known.
In the case of the study of great earthquakes of the Nankai Trough, such as Nankai and Tokai earthquakes, the traces of both earthquakes are entered into the timetable along with the dates of earthquakes known from written records. It can be seen that the great earthquakes of the Nankai Trough have occurred at regular intervals either at the same time or in sequence.
In the case of the Fushimi Earthquake that occurred in 1596, the active fault zone was identified by a trench survey and the damage to castles, temples, and houses was determined from written records. Adding the ground disaster that could be learned from earthquake traces at the archaeological sites, the overall picture of the earthquake can be seen from three perspectives.
When earthquake traces were found at archaeological sites, including tumulus sites, observation of the cross-section of layers could be made by excavating the ground, confirming many important details that were unknown before. In particular, basic knowledge can be obtained by sequential observation of the flow in the layer when liquefaction occurs, up to the arrival of the sand boil at the surface.
In recent years, the awareness of the importance of taking up earthquake traces found at archaeological surveys as subjects of research has diffused widely among archaeologists, along with basic survey methods.
The general public has the impression that the mechanism of earthquakes is difficult to understand. However, by looking at the earthquake traces at an archaeological site, they can easily understand that when a big earthquake struck the area where they reside, it left markings in the past. Earthquake-archaeology is an important educational tool.View full abstractDownload PDF (1575K)
Articles
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Yuki Nakamura, Yoshio Inouchi, Takahiko Inoue, Yoichi Kondo, Fujio Kum ...2013 Volume 52 Issue 5 Pages 203-212
Published: October 01, 2013
Released on J-STAGE: August 10, 2014
JOURNAL FREE ACCESSStratigraphic analysis of acoustic records obtained by “Uniboom” revealed that lake-level fluctuation repeated eight times in Lake Nojiri, Central Japan, during the past 45,000 years. Comparison of the lake-level record among profiles of pollen composition, TOC concentration in Lake Nojiri, oxygen isotope record of NGRIP, and records from the Sanbao/Hulu caves shows that the lake level rose during the abrupt cold stages. In particular, high lake levels correspond with global cooling events such as Younger Dryas, Heinrich events, etc. Factors that caused lake-level rises during cold stages include decreased evaporation because of global cooling and increased snowfall under the enhanced winter monsoon.View full abstractDownload PDF (1589K) -
Kotaro Hirose, Kaoru Yoshioka, Toshiaki Irizuki, Masao Iwai, Toshikazu ...2013 Volume 52 Issue 5 Pages 213-224
Published: October 01, 2013
Released on J-STAGE: August 10, 2014
JOURNAL FREE ACCESSWe verified the significance of a simple and easy treatment using ultrasonic cleaner, which was designed to minimize possible modification of original diatom assemblages preserved in sediments. Our ultrasonic treatment demonstrated that diatom valves incurred little damage ; in addition, this treatment was effective to disaggregate the consolidate structure mainly of fecal pellets. Comparing the diatom assemblages in the samples treated by hydrogen peroxide (an established method for diatom slide preparation) with those processed by ultrasonication, we concluded that the ultrasonic treatment provides a better result in preserving micro and fragile valves that otherwise easily flow out while captured in supernatant during the dacantation process of the hydrogen peroxide method. Furthermore, the investigation of the difference between diatom assemblages in aggregate structures (mainly of fecal pellets) and those in sediment matrix suggests the possibility that diatom analysis of community structures in fecal pellets tends to reconstruct the population dynamics of consumers whose fossils are known to be rarely preserved in underwater sediment.View full abstractDownload PDF (1956K)
Review
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Miki Shiihara, Hanako Domitsu, Masayuki Torii, Yoshitaka Nagahashi, Mi ...2013 Volume 52 Issue 5 Pages 225-236
Published: October 01, 2013
Released on J-STAGE: August 10, 2014
JOURNAL FREE ACCESSUlleungdo is a volcanic island located 130 km east of the Korean Peninsula. The alkaline tephra named Ulleung-Oki (U-Oki) has played an important role as an essential time marker of the early Holocene, especially in paleoenvironmental research in and around the Sea of Japan. During the early-middle Holocene, at least three pumiceous tephras (U-4, U-3, and U-2 in ascending order) covered the island. Therefore, multiple Ulleung tephras are expected to distribute in and around the Sea of Japan. In order to accurately identify and correlate the tephras, it is necessary to consider stratigraphic/chronologic position as well as geochemical/petrographic characteristics. We review previous studies on Holocene tephras from the Ulleungdo volcano, and discuss fundamental methods of tephra correlation and problems for tephrochronology. There is a possibility to revise and fine-tune the stratigraphy of the Holocene tephras from the volcano. The chemical composition of volcanic glass shards is a useful tool for evaluating mixtures of multiple layers. The heavy mineral composition can be also used to identify tephra units. In order to reveal distribution of each tephra unit to a high degree of certainty, characteristics such as heavy mineral and the chemical compositions of each unit must be determined in greater detail.View full abstractDownload PDF (1029K)
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