The extent of deep groundwater flow in mountain belts and its thermal effects are uncertain. Here, we use a new database of discharge, temperature, and composition of thermal springs in the Alps to estimate the extent of deep groundwater flow and its contribution to the groundwater and heat budget. The results indicate that thermal springs are fed exclusively by meteoric water and make up 0.1% of the total groundwater budget. Spring water circulates on average to a depth of at least 2 km. The net heat extracted from the subsurface equals 1% of the background heat flow, which equals an average thermal footprint of 7 km². Cooling by downward flow and heating by upward flow are three and two times higher than the net heat flow, respectively. Comparison with North American orogens shows that hydrothermal activity is higher in areas with high relief or areas under extension.

中文翻译：

---

利用温泉来量化阿尔卑斯山深层地下水流量及其热足迹，并与北美造山带进行比较

山区深层地下水流动的程度及其热效应尚不确定。在这里，我们使用新的阿尔卑斯山流量，温度和温泉成分的数据库来估算深层地下水流动的程度及其对地下水和热量收支的贡献。结果表明，温泉仅由陨石水供给，占地下水总预算的0.1％。泉水平均循环到至少2 km的深度。从地下提取的净热量等于背景热流量的1％，等于7 km ²的平均热足迹。向下流动的冷却和向上流动的加热分别比净热流高三倍和两倍。与北美造山带的比较表明，在起伏较大的地区或延伸范围内的热液活动较高。