CLASSICS 3S03 Study Guide - Midterm Guide: Pyroclastic Flow, Plinian Eruption, Portico

87 views14 pages

Document Summary

Phase 1: air fall phase" or plinian" phase, 18-20 hours, beginning at 1:00 p. m. Accumulation of ash & pumice to around 4 m deep. Cloud that pliny describes as stretching down to the ground is called a nu e ardente ( glowing cloud"), a hot avalanche of ash & gas. Fell most heavily on the south and west sides of the volcano. Two distinct parts to a nu e ardente: ground surge - a ring-shaped cloud of gas & suspended rock fragments. Moves radially outward at high velocity from base of an eruption and leaves the least amount of debris (20-30 cm. of material at pompeii). But the ground surge is the deadliest part of an eruption due to speed and high heat. St. helens ground surge travelled at 200 km per hour: pyroclastic flow occurs after ground surge and is composed of hot avalanches of pumice, ash, and gases. Moves in at high speed after a ground surge.

Get access

Grade+20% off
$8 USD/m$10 USD/m
Billed $96 USD annually
Grade+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
40 Verified Answers

Related Documents