B. SOME EFFECTS OF VOLCANISM

1. BENEFICIAL EFFECTS

¬ gases plus water carried to Earth’s surface from interior created Earth’s atmosphere and hydrosphere

¬ new land created like Hawaii and almost all oceanic islands; the entire ocean floor

¬ fertile soil produced from weathered lava

¬ geothermal energy - Geysers area, N of San Franscisco, Mammoth, Coso, Niland

¬ ore deposits

¬ better understanding of Earth’s interior processes

 

2. DETRIMENTAL EFFECTS

¬ explosions & ash clouds

- Mount St. Helens (1980) - 64 killed

- ash clouds from Vesuvius covered Pompeii (79 AD) and killed 20,000.

- Mt. Pelée - Martinique (1902) - 30,000 killed in St. Pierre

¬ volcanic mudflows or debris flows (lahars; an Indonesian term)

- Nevada del Ruiz - Columbia (1985) - 20,000 killed

- El Chichon - Mexico (1982) - 2,000 killed

- Casitas Volcano - Nicaragua (1999)

¬ tsunamis (tidal waves)

- Krakatau - Indonesia (1883) - 36,000 killed; located west of Java.

¬ social chaos

- Tambora - Indonesia (1815) - 90,000 died from disease and starvation

¬ climate change

- Pinatubo - Philippines (1991) lowered Earth's temperature

- Tambora (1815) caused "year with no summer"

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