GEOLOGY

Detailed explanation-1: -Lava (molten rock) can erupt as fire fountains or lava flows (when it is runny) or as steep-sided domes (when it is viscous). Lava may destroy buildings and infrastructure, but it moves relatively slowly so is rarely a direct threat to people.

Detailed explanation-2: -Reaching speeds greater than 100 kilometers per hour (60 miles per hour) and temperatures between 200° and 700° Celsius (392°and 1292° Fahrenheit), pyroclastic flows are considered the most deadly of all volcano hazards.

Detailed explanation-3: -A volcanic hazard refers to any potentially dangerous volcanic process that puts human lives, livelihoods or infrastructure at risk of harm. Several hazards may affect the area around the volcano, such as lava flows, pyroclastic flows, lahars, jökulhlaups and landslides or debris avalanches.

Detailed explanation-4: -Lava creeps slowly and burns everything in its path but pyroclastic flows destroys nearly everything by land and air, its speed is usually greater than 80 km per hour, but it can reach 400 km per hour.

Detailed explanation-5: -When compared to a lava flow, a pyroclastic flow is much more dangerous. What is a pyroclastic flow? A pyroclastic flow refers to the mixture of gas, rock fragments, and lava that can erupt from a volcano.