أنواع الثورات البركانية
Mosaic of some eruptive structures formed during volcanic activity: An eruption column from a Plinian eruption, Pahoehoe lava flow from a Hawaiian eruption, and a lava arc from a Strombolian eruption.
آليات الثورات البركانية
مؤشر انفجارية البرجان
Volcanic eruptions by VEI index[1]
| VEI | Plume height | Eruptive volume * | Eruption type | Frequency ** | Example |
|---|---|---|---|---|---|
| 0 | <100 m (330 ft) | 1,000 m3 (35,300 cu ft) | Hawaiian | Continuous | Kilauea |
| 1 | 100–1,000 m (300–3,300 ft) | 10,000 m3 (353,000 cu ft) | Hawaiian/Strombolian | Months | Stromboli |
| 2 | 1–5 km (1–3 mi) | 1,000,000 m3 (35,300,000 cu ft) † | Strombolian/Vulcanian | Months | Galeras (1992) |
| 3 | 3–15 km (2–9 mi) | 10,000,000 m3 (353,000,000 cu ft) | Vulcanian | Yearly | Nevado del Ruiz (1985) |
| 4 | 10–25 km (6–16 mi) | 100,000,000 m3 (3.53×109 cu ft) | Vulcanian/Peléan | Few years | Galunggung (1982) |
| 5 | >25 km (16 mi) | 1 km3 (0.24 cu mi) | Plinian | 5–10 years | Mount St. Helens (1980) |
| 6 | >25 km (16 mi) | 10 km3 (2 cu mi) | Plinian/Ultra Plinian | 1,000 years | Krakatoa (1883) |
| 7 | >25 km (16 mi) | 100 km3 (20 cu mi) | Ultra Plinian | 10,000 years | Tambora (1815) |
| 8 | >25 km (16 mi) | 1,000 km3 (200 cu mi) | Ultra Plinian | 100,000 years | Lake Toba (74 ka) |
| * This is the minimum eruptive volume neccessary for the eruption to be considered within the category. ** Values are a rough estimate. Exceptions occur. † There is a discontinuity between the 2nd and 3rd VEI level; instead of increasing by a magnitude of 10, the value increases by a magnitude of 100 (from 10,000 to 1,000,000). | |||||
ثورات الصخور المنصهرة
Magmatic eruptions produce juvenile clasts during explosive decompression from gas release. They range in intensity from the relatively small lava fountains on Hawaii to catastrophic Ultra Plinian eruption columns more than 30 km (19 mi) high, bigger than the AD 79 eruption that buried Pompeii.[2]
Hawaiian
Diagram of a Hawaiian eruption. (key: 1. Ash plume 2. Lava fountain 3. Crater 4. Lava lake 5. Fumaroles 6. Lava flow 7. Layers of lava and ash 8. Stratum 9. Sill 10. Magma conduit 11. Magma chamber 12. Dike) Click for larger version.
Strombolian
Diagram of a Strombolian eruption. (key: 1. Ash plume 2. Lapilli 3. Volcanic ash rain 4. Lava fountain 5. Volcanic bomb 6. Lava flow 7. Layers of lava and ash 8. Stratum 9. Sill 10. Magma conduit 11. Magma chamber 12. Dike) Click for larger version.
An example of the lava arcs formed during Strombolian activity. This image is of Stromboli itself.
Vulcanian
Diagram of a Vulcanian eruption. (key: 1. Ash plume 2. Lapilli 3. Lava fountain 4. Volcanic ash rain 5. Volcanic bomb 6. Lava flow 7. Layers of lava and ash 8. Stratum 9. Sill 10. Magma conduit 11. Magma chamber 12. Dike) Click for larger version.
Peléan
Diagram of Peléan eruption. (key: 1. Ash plume 2. Volcanic ash rain 3. Lava dome 4. Volcanic bomb 5. Pyroclastic flow 6. Layers of lava and ash 7. Stratum 8. Magma conduit 9. Magma chamber 10. Dike) Click for larger version.
Pyroclastic flows at Mayon Volcano, Philippines, 1984.
The lava spine that developed before the 1902 eruption of Mount Pelée
Mount Lamington following the devestating 1951 eruption.
Plinian
Diagram of a Plinian eruption. (key: 1. Ash plume 2. Magma conduit 3. Volcanic ash rain 4. Layers of lava and ash 5. Stratum 6. Magma chamber) Click for larger version.
Phreatomagmatic eruptions
Surtseyan
Diagram of a Surtseyan eruption. (key: 1. Water vapor cloud 2. Compressed ash 3. Crater 4. Water 5. Layers of lava and ash 6. Stratum 7. Magma conduit 8. Magma chamber 9. Dike) Click for larger version.
The fissure formed by the 1886 eruption of Mount Tarawera, an example of a fracture zone eruption.
Hole-in-the-Ground, a large maar in Oregon.
Submarine
Diagram of a Submarine eruption. (key: 1. Water vapor cloud 2. Water 3. Stratum 4. Lava flow 5. Magma conduit 6. Magma chamber 7. Dike 8. Pillow lava) Click to enlarge.
Subglacial
A diagram of a Subglacial eruption. (key: 1. Water vapor cloud 2. Crater lake 3. Ice 4. Layers of lava and ash 5. Stratum 6. Pillow lava 7. Magma conduit 8. Magma chamber 9. Dike) Click for larger version.
Phreatic eruptions
انظر أيضا
المصادر
قراءات إضافية
- Volcanic Ash. University of California Press. 1985. p. 258. ISBN 978-0520052413. Retrieved 5 August 2010.
{{cite book}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - "A transient model for explosive and phreatomagmatic eruptions". Journal of Volcanology and Geothermal Research. Volcanic Eruption Mechanisms - Insights from intercomparison of models of conduit processes. 143 (1–3): 133–151. May 2005. doi:10.1016/j.jvolgeores.2004.09.014. Retrieved 5 August 2010.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - Pyle, D. M. (January 1989). "The thickness, volume and grainsize of tephra fall deposits". Bulletin of Volcanology. 51 (1): 1–15. doi:10.1007/BF01086757.
- "Quantitative shape measurements of distal volcanic ash" (PDF). Journal of Geophysical Research. 108 (B10). 28 October 2003. doi:10.1029/2001JB000818.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - William Henry Mathews (September 1947). ""Tuyas," flat-topped volcanoes in northern British Columbia". American Journal of Science. 245: 560–570.. This is the original landmark paper by William Henry Mathews that first described tuyas and subglacial eruptions.
وصلات خارجية
مشاع المعرفة فيه ميديا متعلقة بموضوع Diagrams of volcanic eruptions.
- USGS Hawaiian Volcano Observatory (HVO) homepage. USGS.
- Distinguishing eruptive types.
- How Volcanoes Work. San Diego State University.