A new campaign was undertaken by Justinian's nephew Germanus Justinus, but he died in 551 CE, succeeded by the general Narses. In 553 CE, Narses defeated Totila and Italy was once again Roman. Justinian's reign lasted almost 40 years, but it was not always popular.
Volcanism is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics and volcanic gases erupt through a break in the surface called a vent.ome of this magma may cool extremely rapidly and will form volcanic glass (rocks without crystals) such as obsidian. Magma that remains trapped below ground in thin intrusions cools slower than magma exposed to the surface and produces rocks with medium-sized crystals.
Geophysical hazards: volcanic eruptions. Definition and characteristics. Volcanic eruptions happen when lava and gas are discharged from a volcanic vent. The most common consequences of this are population movements as large numbers of people are often forced to flee the moving lava flow.Volcanic eruptions often cause temporary food shortages and volcanic ash landslides called Lahar.The most dangerous type of volcanic eruption is referred to as a 'glowing avalanche'. This is when freshly erupted magma forms hot pyroclastic flow which have temperatures of up to 1,200 degrees.he most common consequences of this are population movements as large numbers of people are often forced to flee the moving lava flow. Volcanic eruptions often cause temporary food shortages and volcanic ash landslides called Lahar. The most dangerous type of volcanic eruption is referred to as a 'glowing avalanche'.