Explosive volcanoes present the most danger from pyroclastic flows, ash falls, lahars, landslides, tsunamis and gas emissions. Pyroclastic flows consist of a mixture of hot gas, ash and rock that flow rapidly over the ground. The dense the material is restricted to valley bottoms, while less dense material can travel over hills and ridges. The flows kill by impact, searing and suffocation. Ash falls are a volcanic dust that can travel hundreds and thousands of meters in the air. Major eruptions can change weather patterns when large quantities of ash are distributed into the air. The dust particles absorb sunlight and can affect global weather changes for many years. When ash becomes wet it is heavy and abrasive, which can immerse people and buildings destroying them. People cannot breathe ash; neither can jet engines causing many deaths. Lahars are volcanically generated mudflows produced by the mixing of ash with rain or melting snow, which is present on many volcanoes. Lahars travel in the valley bottoms much like pyroclastic flows and kill by suffocation or flooding. Tsunamis can be extremely dangerous also. Tsunamis are giant waves generated either by an earthquake or entire flank of a volcano crashing into to the water. Many tsunamis occur without notice and many die from flooding on the coastline. Non-explosive eruptions can also present dangers. Lava flows, which generally move slow mainly
Explosive volcanoes present the most danger from pyroclastic flows, ash falls, lahars, landslides, tsunamis and gas emissions. Pyroclastic flows consist of a mixture of hot gas, ash and rock that flow rapidly over the ground. The dense the material is restricted to valley bottoms, while less dense material can travel over hills and ridges. The flows kill by impact, searing and suffocation. Ash falls are a volcanic dust that can travel hundreds and thousands of meters in the air. Major eruptions can change weather patterns when large quantities of ash are distributed into the air. The dust particles absorb sunlight and can affect global weather changes for many years. When ash becomes wet it is heavy and abrasive, which can immerse people and buildings destroying them. People cannot breathe ash; neither can jet engines causing many deaths. Lahars are volcanically generated mudflows produced by the mixing of ash with rain or melting snow, which is present on many volcanoes. Lahars travel in the valley bottoms much like pyroclastic flows and kill by suffocation or flooding. Tsunamis can be extremely dangerous also. Tsunamis are giant waves generated either by an earthquake or entire flank of a volcano crashing into to the water. Many tsunamis occur without notice and many die from flooding on the coastline. Non-explosive eruptions can also present dangers. Lava flows, which generally move slow mainly