No, magma is not infinite. Volcanoes can and do run out of magma.
Magma chambers, the reservoirs of molten rock beneath volcanoes, are finite in size. While they can be replenished over time, the rate of replenishment isn't always enough to sustain continuous eruptions.
Magma Supply Limitations
- Finite Chamber Size: Magma chambers only hold a certain volume of magma.
- Eruption Depletion: Each eruption draws magma from the chamber, reducing its supply.
- Cooling and Solidification: Magma can cool and solidify within the chamber, further reducing the available liquid magma.
- Source Depletion: The mantle, the source of magma, may not provide an inexhaustible supply of new molten rock to recharge the chamber at a sufficient rate.
Volcano Extinction
When a volcano's magma chamber is depleted or the magma supply is cut off, the volcano is considered extinct. The referenced article states that most volcanoes have enough magma for only a few eruptions.
Replenishment
While the mantle provides a source, it is essential to understand that replenishment rates vary. A volcano may become dormant for extended periods while the magma chamber slowly refills, only to erupt again later. However, this recharge process doesn't happen infinitely, or at a rate that would sustain unending eruptions.
