We report the temporal evolution of helium isotopes emission and thermal energy release in the period 2007–2018 at the summit crater of Pico do Fogo volcano, Cape Verde. ³He/⁴He ratio measured in a fumarolic discharge, ranged from 6.69 to 8.63 R_A, being the maximum mantle-derived composition measured in November 2013, one year before the eruption onset in 23 November 2014, and confirm the beginning of a possible magmatic intrusion four years and eight months before the 2014–2015 eruption. ³He and mantle ⁴He emission rates showed similar trends in temporal evolution. Thermal energy release calculated for the study period ranged from 1 up to 72 MW, being the maximum values linked to maximum ³He (1.7 × 10⁻² and 1.5 × 10⁻³ mol d⁻¹ using the first and the second approach respectively), confirming a close relationship between both parameters. After the eruptive event, a simultaneous decrease in R_A, ⁴He and ³He emissions is observed due to the rapid degassing of the magma responsible of the 2014–2015 eruptive process.

我们报告了2007-2018年期间佛得角皮库·杜·福戈火山顶峰火山口中氦同位素排放和热能释放的时间演变。在富马酸放电中测得的³ He / ⁴ He比值范围为6.69至8.63 R _A，这是2013年11月（2014年11月23日爆发爆发前一年）测得的最大地幔衍生成分，并确认了可能的开始岩浆侵入在2014-2015年喷发之前的四年零八个月。³ He和地幔⁴ He的发射速率在时间演化中显示出相似的趋势。在研究期间计算出的热能释放量介于1到72 MW之间，这是与最大值相关的最大值³ He（分别使用第一种方法和第二种方法的1.7×10 ^-2和1.5×10 ^-3 mol d ^-1），证实了这两个参数之间的密切关系。喷发事件后，由于负责2014-2015喷发过程的岩浆快速脱气，观察到R _A，⁴ He和³ He排放量同时下降。