When a volcano erupts, lava comes out. Lava is the molten rock that comes out of vents and fissures created by volcanic activity.Because of its extremely high temperature (over 2,000 degrees Fahrenheit!), lava stays its molten state and flows along any slope. It covers surfaces, like plains. Then it cools, hardens into rock, and eventually stops moving. This is called a lava flow.
Lava flow on the Big Island of Hawaii.
After lava cools
Since the temperature of lava is very high, it takes days or months for lava to completely cool down. When lava cools down, it turns black and forms solid igneous rocks.The outermost layer of the lava flow cools down quickly because it directly interacts with the atmosphere. As a result, it forms a thin black crust and insulates the inside of lava flow. However, because of the insulation, the inside lava is still hot and the cooling down process becomes slower over time.
It takes a long time for lava to completely cool down.
Kilauea volcano of Hawaii is one of the most active volcanoes on Earth.
How lava flows across the ground depends on many factors, such as it’s thickness and the slope of the ground that the lava flow’s on.
The following video is a documentary of Kilauea Volcano’s breakout in 2014. The eruption of the volcano occurred on June 27th. But in November, the lava continued flowing and threatened the nearby towns. If you have never seen lava flows, this is a great video to watch:
How do lava flows affect people?
When a volcano erupts, it becomes dangerous because of the hot lava and toxic gases that come from the eruption. In fact, lava flows are one of the least hazardous of all volcanic activity. As you can see from the above video, lava flows usually do not travel fast so people rarely get killed or hurt. But still, people who live close to the danger zone have to evacuate immediately to avoid lava flows.
If we do not approach close to a lava flow, it does little or no damage to us. However, the most hazardous impact of the lava flow is that it destroys properties. Everything in the path of flowing lava will be buried, surrounded, pushed down, and ignited. For example, lava flow buries cars, blocks roads, and burns houses, plants, and forestland. We cannot stop the flow of lava, only redirect it.