十万个为什么·科学阅读30篇（1）

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科学常识延展阅读·自动延展（批次0001-021）

Volcano behavior depends mainly on magma composition, especially its silica and gas content.
High-silica magma is thick and sticky, trapping gases until pressure builds explosively.
Low-silica magma flows easily, releasing gas steadily and forming broad shield volcanoes.
Water from underground sources can mix with hot rock to trigger violent steam-driven eruptions.
Tectonic setting matters too: subduction zones often produce explosive stratovolcanoes.
Scientists monitor ground swelling, gas emissions, and earthquake swarms to forecast eruption style.
Historic examples like Mount St. Helens show how dome collapse can suddenly change eruption behavior.
Even quiet volcanoes may hide dangerous gas buildup beneath seemingly solid lava plugs.
Computer models now simulate magma movement to improve hazard mapping near populated areas.
Understanding these differences helps engineers design safer buildings and evacuation routes.