The third geophysical survey of Nyiragongo which lava lake appeared on June 21, 1982.

现将在扎伊尔维龙加火山地区进行的第三次地球物理调查结果总结如下。(1)观察到尼拉贡戈火山熔岩湖在没有温度变化的情况下，furmarole的数量有所增加。(2) 1988年Nyamuragira火山口东南部地震活动频繁，1989年4月又发生了新的火山喷发。(3) 1989年喷发后，Nyamuragira火山口的应变扩展达到1 × 10^<-4>。(4)根据大地电磁法，在古喷发地狭长地带发现了一个被解释为部分熔融的高导电性区域。(5) 1975—1989年Nyamuragira火山喷发喷出物中微量元素随时间变化呈基性变化，MgO、CaO含量增加，K_2O、Na_2O含量减少。

The results obtained by the third geophysical survey in Virunga volcanic region, Zaire, are summarized as follows. (1) The lava lake of Nyiragongo was observed to increase in amount of furmarole without temperature change. (2) Seismic activity in 1988 was high at the southeast of Nyamuragira crater, where new eruptions took place in April, 1989. (3) The expansion of Nyamuragira crater reached to a value of 1x10^<-4> in strain after the 1989 eruption. (4) By the magneto-telluric method, a high conductive area being interpreted as partial melting part was found to be along a narrow zone of old eruption places. (5) Aphyric type elements of ejecta from the 1975-1989 Nyamuragira eruptions changed to mafic with time, increasing in amount of MgO, CaO and decreasing in K_2O and Na_2O.