Central Africa's most famous national park, Virunga National Park in Congo (Kinshasa), is home to elephants, lions, hippopotamuses, warthogs, forest hogs, okapis, and mountain gorillas on the volcano slopes.
Its ancient building was constructed on the volcano slopes at about 600 m above sea level.
A plastic scintillator muon telescope is a better candidate to be operated on volcano slopes.
Since electrical power lines will not be available on volcano slopes, one has to design a detector that requires very little power.
This is not trivial, since the most recently frequent eruptions of Ruapehu regard unpredictable phreatic events that may not significantly impact a large area, but certainly is a threat for visitors on the volcano slopes and crater rim.
As the lacking of warning signals makes it impossible to react to threats by means of prompt remedies, so the excess of alarm can produce a tailing-off of attention (as those who live on the volcano slopes know very well), or the loss of credibility of the signal itself (the 'crying wolf' mechanism).
Based on images captured by hikers (e.g., Asahi 2014), when the initial eruption plume reached an altitude of several hundred meters above the summit, the plume began to expand laterally before flowing down the volcano slopes as pyroclastic flow in almost all directions.
Pyroclastic density currents (PDCs), turbulent hot mixtures of fine ash and gas flowing down volcano slopes at high speeds, are common in volcanic explosive eruptions.
As scorching lava rolled 600m down the volcano's slope, 33,000 people from 17 villages in the Guatemalan highlands were quickly evacuated.
Trace gas measurements along two landscape transects (volcano, hill slope) revealed expectedly a mean CH4 uptake (volcano: 76.5 ± 4.3; hill: 28.3 ± 5.3 μg CH4 C m−2 h−1), which is typical for the aerobic soils in this and other steppe ecosystems.
