Lecture 11 - Quote of Day You may melt your metals and cast...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Quote of Day You may melt your metals and cast them into the most beautiful moulds you can; they will never excite me like the forms which this molten earth flows out into. ( Henry David Thoreau ) http://www.bartleby.com/66/97/60797.html Chapter 5 Volcanoes Nature of volcanic eruptions Characteristics of a magma determine explosiveness of eruption Composition (primarily the amount of silica in the magma) Temperature Dissolved gases The above three factors actually control the viscosity of a given magma able 5.1 Viscosity is a measure of a materials resistance to flow Nature of volcanic eruptions http://www.galleryoffluidmechanics.com/misc/buck.htm Low viscosity fluid (e.g., water) High viscosity fluid (e.g., honey) Factors affecting viscosity include Composition (primarily silica content) Higher silica => higher viscosity Lower silica => lower viscosity Temperature Hotter magmas are less viscous Dissolved gases Gas content affects magma mobility Gases expand in magma as it nears Earths surface due to decreasing pressure Violence of an eruption is related to how easily gases escape from magma Nature of volcanic eruptions Si T Explosive Eruptions Nonexplosive Eruptions asaltic lava flows Basaltic lavas exhibit fluid behavior Types of basaltic flows Pahoehoe lava (ropey texture) Aa lava (rough, blocky texture) Figure 5.5 Figure 5.5 B Aa lava flow pahoehoe lava flow Materials extruded from a volcano Types of volcanoes General features Opening at summit of a volcano Crater - summit depression < 1 km diameter Caldera - summit depression > 1 km diameter produced by collapse following a massive eruption Vent surface opening connected to the...
View Full Document

Page1 / 43

Lecture 11 - Quote of Day You may melt your metals and cast...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online