The Ouchigata Plain in western Hokuriku area is interpreted as a tectonic depression bounded on the north and south by northeast-trending reverse faults. The Sekidosan fault on the south displaces geomorphic surfaces of late Pleistocene to Holocene age along its entire length. However, the slip rate and history of Holocene faulting on the fault was not well constrained by previous studies. We have obtained subsurface geologic information by geoslicer and a core sampler across monoclinal scarps 4.6 m high on a Holocene alluvial surface in Hakui City, Ishikawa Prefecture. The samples obtained at 6 sites are 3.5 to 5.3 m long. Correlation of strata and radiocarbon dating show that a peat layer dated at about 6000 years BP is warped into a monocline. The vertical displacement of the top of the peat layer is estimated at 5.2 - 6.1 m, which gives a vertical slip rate of 0.8 - 1.0 mm/yr for the Sekidosan fault. This rate is more than twice greater than previous estimates, which requires a reevaluation of seismic hazards from this fault.

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The Sekidosan fault is a northeast-trending, 33-km-long active reverse fault located along the southeastern margin of the Ouchigata Plain, an elongated tectonic lowland whose northwestern and southeastern sides are bounded by reverse faults. We re-examined precise locations of the surface traces of the Sekidosan fault by interpreting large-scale aerial photographs, and then carried out topographic profiling across the tectonic scarps. Among the 34 profiles, 15 profiles are interpreted to represent the vertical offset associated with the most recent surface-faulting event, which enable us to reconstruct the vertical slip distribution during the most recent surface-faulting event along the middle and northeastern parts of the Sekidosan fault. The amount of vertical offset along the middle part is fairly constant (23 m) along the trace. In contrast, the amount of vertical offset along the northeastern part is smaller (12 m) and tapers off toward the northeastern end. In addition, the amount of vertical offset along other 10 profiles nearly equals to twice the amount of vertical offset during the most recent surface-faulting event, indicating that the amount of offset at individual sites along the middle and northeastern parts of the Sekidosan fault was almost the same during the latest and penultimate surface-faulting events. Subsurface geologic structures and radiocarbon ages obtained by a drilling survey at Nakagawa-Udono site, Hakui City, suggest that a surface-faulting event occurred between 6000 and 4000 years B.P. and this event probably occurred at approximately 4000 years B.P.

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　兵庫県南部地震や東北地方太平洋沖地震といった地震によって引き起こされる過去の大規模地震災害において，共助の重要性と公助の限界が明らかとなった．また，近年では地震災害時において，災害時要配慮者の支援体制の強化が喫緊の課題となっており，災害時要配慮者こそ共助によるケアが必要であると考えられている．本研究では，大規模なアンケート調査から，地域住民による共助を行う意思に関する質的な情報，また，国民健康保険データから共助を必要とする災害時要配慮者数の量的な情報を把握することによって，「質」，「量」の両面からの共助実態を明らかにすることを目的とする．国民健康保険データ及びアンケート調査より得られたデータを活用することにより，「町字」という詳細な単位での共助実態を明らかにすることが可能となった．

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　東北地方太平洋沖地震において，高齢者や障がい者の被害も甚大であったことから，避難行動要支援者の名簿作成が各自治体に義務付けられた．一方，熊本地震において，庁舎の被災等により，名簿が活用できない事例が発生し，平時より避難行動要支援者の精緻な支援計画策定が重要視されている．本研究ではArc GISのNetwork Analystツールの到達圏解析を用い，道路ネットワークを考慮し，避難行動要支援者の避難施設へ到達可能性の検証を行った．本研究では，我が国における超高齢化に伴い，人数が莫大に増加している後期高齢者に着目し，中でも特に避難にケアを必要とする自宅に居住する要介護認定者を分析対象者とした．到達圏解析の結果，要介護認定者の避難時の実態と何人の要支援者が避難所まで到達できない可能性を持つのか，詳細な把握を行うことが可能となった．

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　過去の大規模地災害において公助の限界が明らかになるとともに共助によるソフトパワーの活用が重要視されており，今後起こりうる大規模地震災害へ向け，地域の共助力の向上は不可欠な課題である．本研究では，実際に起こりうる大規模地震災害を想定した上で地域がどの程度の共助を行うことが出来る能力を持つのかといった共助に対するポテンシャルの基礎的評価を行う．さらに医療ビッグデータである国民健康保険データベースの活用から，重篤疾患を持つ災害時における要配慮者を町字単位で把握することにより，地域の共助に対する実態把握を行う．分析の結果，要配慮者数の町字単位の詳細把握が実現し，彼らがどの程度の共助ポテンシャルをもつ地域に居住しているのかを明らかにした．

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The Sekidosan fault is a northeast-trending active reverse fault that extends for about 33 km along the southeastern margin of the Ouchigata Plain, central Japan. We constrained the age and offset of the recent faulting events of the fault by re-interpreting the results of trenching and drilling surveys at three sites, namely Mijiro, Hongo, and Nakagawa-Udono sites. We identified three surface-rupturing events that had occurred during the last 5000 years: 4830-3580, 3690-1990, and 850-250 cal yrBP, and estimated the amounts of net slip during individual events at Mijiro and Nakagawa-Udono sites to be about 1.9-2.2 m and 3.6-3.8 m, respectively. The amount of vertical displacement estimated at Mijiro site is discordant with the slip distribution previously reconstructed based on tectonic geomorphological investigations. This is probably due to the lack of a tectonic scarp associated with only the latest event around the site. On the other hand, the amount of vertical displacement estimated at Nakagawa-Udono site is consistent with the slip distribution. So, we suggest that the previous slip distribution is appropriate to a certain extent. The length of surface rupture calculated from the amounts of the net slip using empirical relationships is at least 25-30 km, indicating that at least three quarters of the entire length of the Sekidosan fault rupture during individual events. Recurrence interval and slip rate of the fault are estimated at 1400-2300 years and 1-3 mm/yr, respectively.

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