How Do We Know A Volcano Will Erupt?

Introduction

Predicting a volcano to erupt is very difficult.
Some volcanoes have erupted constantly, such as Kīlauea in Hawaii.
However, some have hundreds or even thousands of years between eruptions.
Today, we can predict more accurately than 20 years ago, thanks to the development of new or improved techniques.

First, it is very important to know volcanic activity in the past because they have different behaviors.
Scientists, known as volcanologists, will study the material from the volcanic eruption.
When it erupts slowly, it will form a lava flow, consisting of igneous rock. These rocks will cool and solidify to form a hard rock layer.
There are also volcanoes that erupt accompanied by explosions. The result of this explosion is rock fragments, crystals, and volcanic glass (rock that has frozen rapidly on the surface).

Studying these materials can help volcanologists understand how violent eruptions are and how often volcanoes erupt with explosions.
Volcanologists can predict volcanic eruptions using several techniques.
The surface of the volcano will become hot, because magma (underground molten rock that flows out as lava when a volcano erupts) moves closer to the surface before eruption.
This can be monitored by means of detection devices on heat measuring satellites.

Detection from space

The surface of a volcano can rise or fall during the movement of magma below the surface.
It can be detected at the bottom, but can also be measured from space with satellites using radar.
The way volcanic motion detection works is to study each change over a period of time to bounce radio waves from satellites onto the volcano and back again.
This time will be shorter if the volcano shows an ascension.
Monitoring volcanoes from space is now common practice.
This method is safer and cheaper than having to visit a volcano, especially if it is erupting or in a very remote area.

Another way to see when a volcano is about to erupt is to measure the gas that is coming out.
When magma moves to the surface, the gas quickly escapes and precedes the magma.
This gas can be measured from space or from land.
When the gas mixture coming from the volcano changes, this can indicate that the magma below is moving.

Magma that moves

Volcanologists often use two other methods to see if mountains will erupt.
When magma moves, it vibrates the land, creating a type of earthquake called harmonic vibrations.
These vibrations can indicate how fast and where the magma is moving.
The second method is gravity measurement.
Gravity is, of course, the force that stops everything from escaping from Earth's surface into outer space.
However, the strength decreases slightly as the surface becomes less dense.
This does not mean the object will immediately fly into orbit because the changes are very small.
However, we can measure a tool called gravimeters.
Liquid rock has a lower density than when it is solid, so a volcano's lower area of gravity, especially if they change over time, may indicate magma - and possible eruptions.
By studying the history of volcanoes and combining information from various terrestrial and celestial techniques, we can understand and warn the people living near the volcano before the eruption.