Behavior volcano

Volcanic behavior (also known as volcanic activity) refers to all phenomena and behavioral changes that occur in volcanoes due to the movement of magma within the Earth. This behavior includes the signs before an eruption, the manner in which they erupt, and their activity level.

In general, volcanic behavior can be divided into three main phases:

1. Behavior Before Eruption (Pre-Volcanic Symptoms) When magma begins to rise to the surface, the volcano will show changes in the behavior of the surrounding environment:

• Increased Volcanic Earthquakes: Local vibrations or earthquakes occur due to magma pressure pushing rocks inside the mountain.

•  Increased Crater Temperature: The temperature around the crater and slopes increases sharply because the position of the magma is getting closer to the surface.

• Water Sources Drying Up: The increase in temperature causes springs around the mountain to evaporate and dry up. 

• Wildlife Migration: Animals that live in mountain forests (such as monkeys and birds) will descend the slopes because they feel restless due to the heat and vibrations.

• Plants Withering: Vegetation around the crater dries up and withers due to the soil temperature being too hot.

2. Behavior During Eruption (Eruption) The behavior of a volcanic eruption is highly dependent on the viscosity of the magma and the gas pressure within it. The eruption pattern is divided into two types:

•  Effusive (Melting): Magma is liquid with low gas pressure. The characteristics of the eruption tend to be calm, where the lava simply melts out of the crater and flows down the slopes. An example is the character of Mount Mauna Loa in Hawaii.

• Explosive (Explosion): Thick magma with very high gas pressure. The volcano will erupt with a powerful bang and eject solid material (bombs, lapilli), volcanic ash, and hot clouds (wedhus gembel) into the air. Examples include Mount Merapi and Mount Krakatoa.

Understanding Volcano Alert SystemsDifferent countries use distinct numerical or descriptive tiers to communicate volcanic activity to the public and aviation sectors.

Indonesia (PVMBG / Magma Indonesia)Indonesia uses a four-tier alert system managed by the Center for Volcanology and Geological Hazard Mitigation

• Level I (Normal): Background activity with no abnormal changes.

• Level II (Waspada / Caution): Elevated baseline activity or minor localized unrest.

• Level III (Siaga / Alert): Heightened activity or active eruptions with visible changes; public should avoid immediate zones.

• Level IV (Awas / Highest Alert): Imminent or ongoing major eruption requiring immediate evacuation