shallow layer

基本解释

According to the results in analysis of the sample water quality, it evaluates the shallow-layer groundwater quality in the urban planning area.
根據水質取樣分析結果，對區內淺層地下水水質進行評價；
The results of shallow-layer apparent density mapping reveal that: ① The crustal density in Sichuan basin is higher than that in Songpan-Ganzi orogenic zone;
淺層重力異常的密度填圖表明①四川盆地地殼密度較高，松潘—甘孜造山帶密度較低；
The groundwater resources in Suzhou Urban Planning Area are abundant, but previous application and study are related to the deep-layer groundwater more than the shallow-layer groundwater.
囌州城市槼劃區內地下水資源豐富，但是以前相關的應用、研究主要是針對深層地下水，而淺層地下水較少涉及。

The thinking is that you could bury a small reactor in a shallow layer of bedrock, perhaps 30-50 meters underground.
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