Let's look at what causes these volcanic eruptions. The answer is radioactivity.
Radioactivity is the phenomenon where elements release energy due to the instability of the nucleus. There are three types of radiation. The first is alpha radiation. Alpha radiation is when helium nuclei, or protons, are emitted at high speeds from a radioactive element. Because alpha particles are relatively large, they have little power to penetrate objects, and are not considered to be very harmful.
Beta radiation occurs when electrons are emitted at high speeds from radioactive nuclei. Electrons have a much higher penetrating power because they are smaller than protons. Beta radiation can penetrate several millimeters into the skin.
The third, and most powerful form of radiation, is gamma radiation. Unlike alpha or beta rays, gamma rays have no electrical charge. This type of radiation is by far the most dangerous. Gamma rays may pass completely through the human body. To stop gamma rays, thick pieces of concrete or lead are required.
Elements which have unstable nuclei can also undergo fission or fusion, depending on the element, to become stable.
Nuclear fission is a highly exothermic process by which a heavy nucleus splits into two lighter, more stable nuclei.
Nuclear reactors utilize this process to create energy by inducing a controlled chain reaction of nuclear fissions. This process generates mass amounts of heat, which drives an electric generator.
Nuclear fusion is the opposite process. In this reaction, two lighter, unstable nuclei combine to give a heavier nucleus which is more stable. This reaction also produces releases large amounts of energy. However, nuclear fusion requires a temperature much to high to be used for practical purposes.