Northern Kyushu Research Articles

Agent-Based Geosimulation of Yayoi Period Population Dynamics in Kyushu, Japan

Current scholarship in Japanese archaeology recognizes the people and culture of the Yayoi period as being descended from both continental migrants (Toraijin) and the native inhabitants (Jomon people). However, the number of migrants that came to Japan and the degree to which they were directly responsible for the development of Yayoi culture is a topic of debate. Using northern Kyushu as a case study, the author employs an agent-based simulation based on geospatial data to model the spread of population, rice agriculture, and continental genetics during the Early Yayoi period. Multiple simulations are performed with varying parameters related to migrant population size, marriage customs, and the ratio of men to women amongst migrants to test their effect on the demographics of the Yayoi period. Simulation results were compared to population estimates and the distribution of mitochondrial DNA in order to determine their validity. Experiment 1 showed that the average number of continental migrants was likely in the order of magnitude of 10s of people per year (approx. 40 to 50) during the first 500 years of the Yayoi period. Experiment 2 demonstrated that polygyny can lead to increased population growth and aids in the spread of continental genetics, but without more rigorous evaluation criteria it is difficult to conclude whether it was practiced during the period. The methods used in this study demonstrate how agent-based simulations can model realistically sized populations moving through geographic space by basing simulation inputs on geospatial data and population estimates.

Identification of dietary patterns and their relationship with zinc intake in male and female workers

Objectives Deficiency of zinc, an essential trace element in the body, adversely affects taste, wound healing, and immunity. This study aimed to identify the dietary patterns of male and female workers using factor analysis and clarify the relationship between dietary patterns and zinc intake.Methods The participants were 395 municipal employees (193 men and 202 women) in Northern Kyushu aged 19-71 years. To obtain the dietary intake data, participants were asked to complete a lifestyle and health questionnaire and brief self-administered dietary history questionnaire. Zn intake was evaluated per 1,000 kcal (mg/1,000 kcal). The values were adjusted for energy using the density method, and multiple regression analysis was performed.Results Three dietary patterns were identified for each participant. Among men, "main and side dish type pattern" characterized by higher intakes of potatoes, legumes, vegetables, seafood, meat, and low for cereals, "snack type pattern" characterized by higher intakes of sweets and coffee, and "Mediterranean diet pattern" characterized by higher intakes of bread, pasta, fruits, eggs, and milk, and low for miso soup and rice were identified. For women, a "vegetarian diet type pattern" characterized by higher intakes of beans, vegetables, mushrooms, and seaweed, "main and side dish type pattern" characterized by low intake of rice, and "dinner-time drinking pattern" characterized by higher intakes of alcoholic beverages were identified. Zinc intake was positively associated with the "main and side dish type pattern" and "Mediterranean diet pattern" in men and "vegetarian diet" and "main and side dish type pattern" in women. Additionally, zinc intake was negatively associated with the "dinner-time drinking pattern" among women.Conclusion Despite adjusting for age, BMI, marriage, occupation, smoking habits, and exercise habits, the "main and side dish type pattern" and "Mediterranean diet pattern" were positively correlated with zinc intake in men and the "vegetarian diet" and "main and side dish type pattern" in women. The data suggest awareness of the dietary patterns that are conducive to ensuring zinc intake.

Seismic Hazard Assessment in the Southeastern Korean Peninsula for Large Earthquakes in Northern Kyushu, Japan: A 3D Numerical Simulation of Pseudodynamic Rupture Scenarios

Abstract Active fault segments in the Northern Kyushu area are of concern in seismic hazard analysis of the southeastern Korean Peninsula (KP) due to their proximity. In this study, we numerically simulate the peak ground motions at the southeastern KP for Mw 6.7–7.1 earthquake scenarios at five major active fault segments located in northern Kyushu: Kego SouthEastern, Nishiyama OshimaOki, Nishiyama Nishiyama, Kikugawa Central, and Kikugawa Northern fault segments. We conducted fully 3D seismic-wave propagation simulations integrating 3D seismic velocity model and earthquake scenarios generated through pseudodynamic rupture modeling. After applying the region-specific attenuation value, the predicted peak ground velocities (PGVs) ranged from 0.18 cm/s (modified Mercalli intensity [MMI] III) to 26.76 cm/s (MMI VIII), depending on the earthquake scenarios. The PGV distributions were influenced by several factors, such as crustal velocity anomalies, rupture directivity, and the distribution of source parameters on the fault plane. Despite the fixed fault geometries, magnitudes, and hypocenters, significant variations in peak ground-motion distributions were simulated due to differences in the source statistics. The estimated probability density distributions of PGV indicated a significant likelihood of peak ground motions surpassing 20 cm/s in the Yeongnam Province. Furthermore, we identify a linear relationship between the average PGV values and standard deviation across 20 scenarios for each fault segment, to quantify the uncertainty in the PGV distributions.

북부 규슈 마한 교류 네트워크의 변천 및 구조 연구

Records implying the interaction between the Korean Peninsula and the Japanese archipelago are found in works such as the 『漢書地理志』 and the 『魏志倭人伝』. In addition, considering that the Nakrang (樂浪)·Daebang (帶方) route was inevitably through the Mahan region, it can be seen that Mahan was also located within the Korea-Japan interaction network. This is evidenced by the large number of Mahan pottery found in northern Kyushu, where various Korean Peninsula-type pottery are concentrated. This article attempts to estimate the location and operational strategy of the Mahan interaction network from a comparative perspective, paying attention to the specificity of the logistics environment in northern Kyushu. The temporal and spatial aspects of Mahan type pottery excavated from northern Kyushu are re-examined and compared with those of the Nakrang and Byeon·jinhan(弁·辰韓) type pottery that were introduced at the same time. Through this, it can be admitted that the Mahan interaction network has been organized since the second half of the late Yayoi period, but it is judged that they have taken advantage of and participated in the network established around Nakrang in the past. Mahan's new initiative is recognized in the process of dismantling and reorganizing existing networks from the beginning to the first half of the Early Kofun Period. Furthermore, by looking at the background of the establishment and dismantling of the Nishijinmachi[西新町] ruins, which are the inflection points, from a relative perspective and operational strategy, the possibility that they had a trade structure vulnerable to risk management was pointed out. Through the above results, it was possible to estimate the specific status and role of the Mahan interaction network identified in northern Kyushu. It was possible to evaluate Mahan's external capabilities in a new position during the Proto-Three Kingdom Period, which had previously received relatively little attention as part of the Samhan or as part of the Baekje. Through this, it is expected to be a study that can contribute to the reconstruction of the multifaceted and comprehensive aspects of external relations formed by Mahan while evoking research on Korea-Japan interactions during the Proto-Three Kingdom Period.

Health and Safety Education for Painting Workers in Small Companies to Make Them Aware That Paint Is "Dangerous and Harmful".

Workers in painting companies may be unaware that the paints they handle have adverse health effects. The present study explored the factors associated with workers' perception of paints as "dangerous and harmful". A questionnaire survey and interviews were conducted with workers engaged in painting operations in small-sized painting companies (fewer than 50 employees) in northern Kyushu and Yamaguchi prefectures. Safety and health education methods making workers perceive paint as "dangerous and harmful" were clarified. Fisher's exact test and logistic regression analysis were used for the survey and hierarchical cluster analysis for the interviews. The factor "Hazard prediction activity (KY Activity)", gender, and job position were identified as factors that make workers perceive paint as "dangerous and harmful". Based on the interview results, "KY Activity" was a keyword and a standardized safety and health activity. Before work, workers gather in a small group to discuss the dangers and hazards of paint, share information, establish action goals, and confirm safety measures. The questionnaire identified "KY Activity" as a factor influencing the workers' perception of paint as "dangerous and harmful". "KY Activity," also extracted from the interviews, is an effective health and safety education method for teaching workers in small-sized painting companies that paint is "dangerous and harmful".

A New Snaggletooth Shark Species, Hemipristis tanakai Sp. Nov., from the Ashiya Group (Oligocene), Northern Kyushu, Japan

A New Snaggletooth Shark Species, Hemipristis tanakai Sp. Nov., from the Ashiya Group (Oligocene), Northern Kyushu, Japan

Characteristics of beech mixed forest distributed at low elevations on Mt. Toishi, northern Kyushu, in the upper warm‐temperate zone of Japan

AbstractThe aim of this study was to clarify the structure and regeneration status of mixed beech (Fagus crenata) forest on Mt. Toishi in the Sangun mountain range in northern Kyushu, a relatively low‐latitude region in Japan, with emphasis on forests at lower elevations. We focused on a mixed beech forest at a low elevation of Mt. Toishi and compared the forest structure of the target stands, including tree species and size, with the forest structure near the peaks of Mt. Toishi and Mt. Sangun. Deciduous broad‐leaf trees were dominant near the peaks, while evergreen broad‐leaf trees dominated at lower elevations, whereas the relative dominance of beech trees was not significantly different. Near the peaks, the number of large‐diameter beech trees forming the canopy decreased, and small‐diameter trees were present. The proportion of small‐sized trees was lower in the low‐elevation forest area than in the forest area near the peak. Even at lower elevations, juvenile beech trees grew in limited areas on steep slopes along forest roads. These sites suggested that regeneration of beech populations is possible even at low elevation.

Comparative morphological analysis reveals a new record of <i>Boehmeria nakashimae</i> (Urticaceae) in Korea

A newly recorded species, <i>Boehmeria nakashimae</i> Yahara, is confirmed for the first time to be distributed on forest edges on Jejudo Island, Korea. This species is known to be endemic to northern Kyushu, Japan. It is characterized by ovate to broadly ovate, ellipticovate, or sub-orbicular middle leaf shapes, serrulate-dentate and uniform margins, 17–29 teeth on one side, a short caudate or narrowly acute apex, dense glomerules at fruiting, and densely strigillose on the stems, both surfaces of the leaves, the perianth of staminate flowers, and achenes. Therefore, it is given the new name ‘Je-ju-top-mo-si-pul’ in Korean based on its serrulate-dentate leaf margin and geographical distribution. A description, photographs, illustrations, and keys of related taxa in Korea are provided.

Parent magma of the Cretaceous Northern Kyushu batholith and heat source of large-scale igneous activity: Petrological constraints on magmatism of the Northeastern Asian continental margin in the Cretaceous period, example for the Kita-Taku mafic complex in northern Kyushu, SW Japan

The Japanese island in the Northeastern Asian continental margin is located in a subduction zone, and granitoid covers about 30% of the island arc. The Cretaceous Northern Kyushu batholith (CNKB) is classified as 19 bodies based on previous studies and consists of a granitic body and a small amount of associated mafic bodies. Of these, the Kita-Taku mafic complex body (KMC) mainly consists of gabbroic rocks and can be classified into cumulus textures (Cumulus group: Types 1–4) and those without (Non-cumulus group: Types 5–7), which can provide information on the heat source of the large-scale igneous activity in northern Kyushu from the Northeastern Asian continental margin at Cretaceous period.Melt compositions inferred from the high Mg# pyroxene compositions of the olivine-bearing pyroxene hornblendite (Type 1) member of KMC were estimated using melt-pyroxene partition coefficients. The clinopyroxene-bearing equilibrium melts are similar to the Sanukitic high-Mg andesite (HMA) in multi-element and rare-earth element patterns. Besides, the trace element and rare earth element patterns of the Cretaceous high-Mg diorites (HMDs) in northern Kyushu have similar patterns to the clinopyroxene-bearing equilibrium melts of the KMC and Sanukitic HMA magma. This implies that Sanukitic HMA magmas were substantially activated in northern Kyushu during the Cretaceous period.Analysis of the parent magma (heat source) and the small-scale plutonic bodies that consist of CNKB indicates that the essential granitic magma is formed by partial melting of the lower crust and mixing with mantle-derived Sanukitic HMA magma. The Sanukitic HMA magma could be the parent magma for the heat source and crustal growth. The lithofacies of CNKB can be reconstructed from the examination of small-scale plutonic bodies due to the mixing and assimilation of various end-member magmas and crustal materials, and their associated differentiation and accumulation processes. As the Northeastern Asian continental margin during the Cretaceous is assumed to be situated within the extensional setting due to slab rollback, the results of this study provide new insights into the complicated batholith formation processes and heat source.

Characterization of the iron sand collected from the foot of Mt. Aburayama (Fukuoka, Japan) for estimating the origin of archeological iron artifacts from northern Kyushu

AbstractThe iron sand around Mt. Aburayama (Fukuoka, Japan), where various ancient iron‐making sites are located, was investigated to establish a research infrastructure for identification of the raw material used in the archeological iron artifacts excavated from this area. Iron sand samples were magnetically collected from the rivers flowing in this area and nearby outcrop soil. The samples were qualitatively analyzed using Mössbauer spectroscopy and x‐ray diffractometry to identify the minerals present inside them. Additionally, the elemental concentrations in these samples were determined using x‐ray fluorescence spectrometry. The iron sand samples were characterized by comparing them with those from other Japanese regions using scatter diagrams developed based on the elemental concentrations in the samples. The scatter diagrams showed clear distinctions between the iron sand samples from the Mt. Aburayama area and other Japanese regions. These diagrams may enable us to clarify the relationship between the iron sand and archeological iron artifacts found in the vicinity of Mt. Aburayama.

Impact of forest type and age on shallow landslide susceptibility: a case study from the 2017 heavy rainfall in northern Kyushu, Japan

ABSTRACT Assessing the impact of forest type and age on shallow landslide susceptibility is important for managing protective functions of forests. Previous studies have examined the correlation between forest types and ages, and shallow landslide susceptibility, but causal effects of forest type and age on shallow landslide susceptibility are yet not clear. This study investigated the causal effect of forest type and age on shallow landslide susceptibility using a propensity score method by combining existing geo-data sets. Here, we focus on shallow landslides caused by an extreme rainfall event on 5–6 July 2017, in the mountainous areas of Asakura City and Toho Village, Fukuoka Prefecture, Japan. Randomly located samples of coniferous forest, broadleaved forest, and young forest exposed to shallow landslide events were analyzed. The inverse probability of treatment weighting with the propensity score was applied to the samples to compare the differences in shallow landslide susceptibility among the three forest classes. Young forest had increased shallow landslide susceptibility, compared with coniferous forest and broadleaved forest, by 3.70 × 10−2 and 4.12 × 10−2, respectively, which corresponded to a two to three times increase in shallow landslide susceptibility when the forest changes from coniferous or broadleaved forest to young forest. No significant difference in shallow landslide susceptibility between coniferous forest and broadleaved forest was observed. These differences in shallow landslide susceptibility should be considered when implementing forest management schemes.

Development of forecasting method of time variation of net solar output over wide area using grand data based neural network

This paper focuses on the short-term forecasting of the temporal variation in the net output of photovoltaic power generation across a wide area. Due to the unstable output fluctuations of photovoltaic power generation, thermal power generation is necessary. However, to handle unpredictable power fluctuations, thermal power often operates in a no-load standby mode, resulting in wasteful energy consumption. To address this issue, we have developed a novel prediction method that utilizes neural networks for short-term forecasting of the net output of photovoltaic power generation in a wide area. The key aspect of this method is the utilization of the distributed solar power generation itself as a sensor within the target area, enabling the use of BIG DATA derived from the sensor to predict future net output of solar power generation using a neural network. To expedite calculations, we have incorporated an autoencoder and a decoder. We applied this methodology to northern Kyushu and conducted thorough verification. Furthermore, we compared the persistent model with the smart persistent model and demonstrated their effectiveness as viable solutions.

Magma evolution and growth process of the Ushikiri-yama granodiorite body a member of the Cretaceous Northern Kyushu batholith, SW Japan: Implication for the crustal forming and growth of the initial Cretaceous plutonic activity in northern Kyushu along the East Asian active continental margin

The ascending and emplacement processes of granitoid magma combined with magma genesis are essential in intrusive rocks of various scales. This study is performed to reconstruct and re-evaluate the formation of the Ushikiri-yama granodiorite body, a small-scale plutonic body in the Northern Kyushu batholith. The Ushikiri-yama granodiorite occurs as a laccolith, which can be classified into the south and north bodies. Both bodies are situated along the low-angle rigidity boundary of the host rocks between crystalline limestone and pelitic-psammitic metamorphic rocks. Magmatic foliation and lineation reveal that the granodiorite magma extends to the south and north from the central region of the Ushikiri-yama granodiorite to form a laccolith. The zircon UPb dating of the south and north bodies presents ages of 112.1 ± 0.8 and 110.8 ± 0.6 Ma, respectively, which indicates that the granodiorite magmas are active at different pulses. These ages correspond to the initial stage of the Northern Kyushu batholith. The Ushikiri-yama granodiorite magma ascends from the source region through the same conduit with at least two pulses and is located at the shallow crustal level, utilizing the low-angle rigidity boundary to form a small-scale laccolith as a pioneering magmatic activity of the Northern Kyushu batholith. As the northern region of Southwest Japan and the southern region of the Korean Peninsula during the Cretaceous are assumed to be situated within the extensional setting due to slab roll-back, the results of this study provide new insights into the complicated batholith formation processes and crustal evolution under the extensional regime.

戦時期日本における建物疎開の展開に関する制度史的研究（その１）：事業対象都市の変遷と事業施行の実態

Early building evacuations focused on cities critical to air defense, but the target cities were officially expanded in June 1945, and in reality, they were expanded around the end of 1944 to include small and medium-sized regional cities. The largest number of evacuated buildings was recorded around March 1945, when nighttime air raids on major cities were common. Although the project was implemented in many cities throughout Japan, the majority of evacuated buildings were concentrated in the industrial areas of Keihin, Keihanshin, Nagoya, and northern Kyushu.

Proposed Countermeasures against Woody Debris Damage Considering Runoff Characteristics

In recent years, a combination of forestry decline and global climate change has led to heavy rains and landslides in Japan that have caused extensive forest damage through woody debris outflow. The current configuration of impermeable sabo dams has insufficient capacity to capture woody debris under these conditions; therefore, improvements to permeable sabo dams, which have a high woody debris capture capacity, are underway; these sometimes involve the addition of steel fittings. In this study, we examined the effectiveness of such measures in consideration of the factors affecting woody debris flow. After reviewing a woody debris outflow that occurred during a heavy rain disaster in northern Kyushu, Japan, we propose woody debris countermeasures that consider basin and runoff characteristics. Our results indicate that woody debris flow occurs later than sediment flow. Therefore, we performed experiments to test the effectiveness of various methods to slow water flow using the terrain conditions at the nearest valley outflow point. Finally, we propose woody debris countermeasure policies considering basin characteristics, to promote the future preservation of river basins.

Effect of One-step Shallow Tillage Planting Method Using an Up-cut Rotary for Preventing the Reduction of Soybean Yield under Climate Risk Conditions in Northern Kyushu

Effect of One-step Shallow Tillage Planting Method Using an Up-cut Rotary for Preventing the Reduction of Soybean Yield under Climate Risk Conditions in Northern Kyushu

The Process and Challenges of Resident-Led Reconstruction in a Mountain Community Damaged by the Northern Kyushu Torrential Rain Disaster: A Case Study of the Hiraenoki Community, Asakura City, Fukuoka Prefecture, Japan

Frequent torrential rainfall disasters have occurred worldwide in recent years. In Japan, the Northern Kyushu Torrential Rainfall disaster in July 2017 caused extensive damage to Fukuoka and Oita prefectures and significantly impacted local landscapes, from which residents derive pride and identity and, hence, are of the utmost importance. Local communities in Japan are also at risk of extinction due to progressive depopulation. This study discusses community revitalization through landscape creation and related challenges based on the case of the Hiraenoki Community affected by the Northern Kyushu Torrential Rainfall disaster. We conducted long-term participant observations over two years and semi-structured interviews with all households in the community. We found that the landscape project revitalized local pride and involved numerous people outside the community, including the prefectural extension center, university, and Non-Profit Organization (NPO), and provided them with an opportunity to connect. On the other hand, our investigation also revealed the danger of obscuring the original purpose of reconstruction activities because of collaboration with outsiders. This case study elucidates the possibilities and challenges of resident-led reconstruction activities in communities that are facing depopulation and aging problems and are working with organizations within and outside the community.

Topographical criteria for the occurrence of landslides causing debris flows in the 2017 torrential rain in northern Kyushu, Japan

In the volcanic rock fields around Hita City, 19 landslides occurred in the 2017 torrential rains in northern Kyushu, 11 of which triggered debris flows. In order to mitigate debris flows disasters caused by landslides, it is important to assess the points where landslides are most likely to occur. Therefore, topographic profiles of landslide and non-landslide slopes were calculated from digital elevation models obtained before the disaster. The results indicate that there is a topographic criterion for landslide occurrence in the relationship between the topographic position index (TPI) and the tangent Laplacian.

Characteristics of the Environmental Conditions for the Occurrence of Recent Extreme Rainfall Events in Northern Kyushu, Japan

Characteristics of the Environmental Conditions for the Occurrence of Recent Extreme Rainfall Events in Northern Kyushu, Japan

Reexamining Ceramic Standardization During Agricultural Transition: A Geometric Morphometric Investigation of Initial – Early Yayoi Earthenware, Japan

Abstract The quantifiable and reproducible representation of variability in material culture has continued to play a key role in the elucidation of shifting patterns of production organization in prehistoric archaeology. The study of standardization of ceramics has traditionally illuminated on how agents shift means of production to a common goal. However, while geometric morphometric (GMM) approaches to standardization quantification overcome issues of reproducibility faced in traditional literature, the lack of widespread radiocarbon dating in Japan requires adherence to traditional methods of temporal control. This study seeks to extrapolate ceramic standardization in a quantifiable means, while also maintaining temporal control utilizing traditional methods. In a pilot case study of the agricultural transition period of the Yayoi period of the Japanese peninsula (∼900/800 BC–300 BC), results of mortuary vessels show that while a previous model based on visually determined traditional methods assumed that ceramic manufacture was centralized in the Hakata Bay subregion of the northern Kyushu island region; utilizing GMM analysis to extrapolate variable standardization is able to identify a decline in morphological variation, despite increases in population density and potential variability between migrant and indigenous production patterns. These results further illuminate the strong correlation between production intensity and its effect on standardization practices in material culture production, as seen in modern ethnoarchaeological literature.