gelifluction

Japanese: gelifluction

...In areas where snow remains late into the summer as snow patches or snow fields, water that melts from the snow seeps into the surrounding rocks and soil during the day and freezes at night, breaking up the rocks (freeze-fracture), and the resulting rock fragments are carried downslope by the meltwater. The surface soil becomes mushy and saturated with meltwater, slowly moving downward (geliflux). Erosion around the snow occurs as a result of the freeze-fracture process and the removal of fractured material by meltwater and geliflux, forming shallow depressions called snow niches or nivation hollows.

From Mass Movement

In periglacial regions, water is drawn up from the lower layer into the frozen soil, and is released as ice during thawing. In addition, meltwater from snow is added, and the frozen soil remaining in the lower layer is impermeable to water, making it more likely to become saturated. Solifluction occurs more frequently than in other regions. This type of melting of frozen soil is sometimes called gelifluction to distinguish it from other types of melting.
[Rapid Flow]
When a large amount of water is suddenly added to fine-grained sediments such as volcanic ash, sand, and clay, or to a layer of rock debris that contains a large amount of these materials due to rainfall, melting snow, groundwater seepage, or volcanic activity, a high-velocity flow of slope material occurs.

*Some of the terminology that mentions "gelifluction" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…残雪が，雪渓や雪田として夏に遅くまで残る所では，昼間，残雪からとけ出した水分が周囲の岩石や土壌中にしみこみ，夜には凍結するので岩石が破砕され(凍結破砕作用)，生じた岩片は融雪水によって斜面下方へ運ばれる。また融雪水で飽和されてどろどろになった表層の土壌は，下方に向かってゆっくりと移動する(ジェリフラクションgelifluction)。凍結破砕作用と，融雪水･ジェリフラクションによる破砕物質の除去によって，残雪の周囲では浸食が進み，雪窪（ゆきくぼ）snow niche,nivation hollowとよばれる浅い凹地が発達する。…

【マス･ムーブメント】より

…周氷河地域では，凍土中に下層から吸い上げられ氷として析出していた水が，融解時に放出されるうえに融雪水が加わり，さらに下層に残る凍土が水をとおさないので飽和状態をつくりやすく，他地域よりもソリフラクションが活発に起こる。このような凍土の融解によるものを，ジェリフラクションgelifluctionと呼んで他と区別することがある。
［急速な流動］
　火山灰や砂，粘土など細粒の堆積物やそれらを多く含んだ岩屑層に，降雨，融雪，地下水の湧出，火山活動などで急に多量の水が加わると，速度の大きな斜面物質の流動が起こる。…

※「gelifluction」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典第２版について | 情報

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