GEOL 106 Lecture Notes - Lecture 19: Mount Vesuvius, Landfall, Turbulence

5.9 Perception of and Adjustment to the Volcanic Hazard

PERCEPTION OF VOLCANIC HAZARDS

- people live near volcanoes for:

1. they were born there and in case of some islands, such as Canary Islands, all land is volcanic

2. land is fertile and good for farming

3. people are optimistic and believe an eruption is unlikely

4. they cannot choose where they life (e.g. limited by economics)

ADJUSTMENTS TO VOLCANIC HAZARDS

- psychological adjustments to losses

- primary human adjustment to volcanic activity is evacuation

o e.g. Mount Vesuvius with 3 million people living in surrounding area

ATTEMPTS TO CONTROL LAVA FLOWS

- hydraulic chilling and wall construction have been employed to deflect lava flows away from

populated or otherwise valuable areas → mixed success

- favourable conditions:

1. slow movement of flows allowed time needed to control effort

2. transport by sea and roads allowed delivery of pipes, pumps, heavy equipment

4.1 Introduction to Tsunamis

- tsunami: large harbor waves, produced by sudden vertical displacement of ocean water

o may be triggered by: large earthquakes that causes rapid uplift or subsidence of seafloor;

underwater landslide that may be triggered by earthquake; collapse of part of volcano that

slides into sea; submarine volcanic explosion; impact in ocean of an extraterrestrial object

(asteroid/ comet)

o asteroid impact can cause mega tsunami

o those produced by earthquakes are most common

- damaging tsunamis in historic times most related frequently in Pacific Basin: pg. 102

HOW DO EARTHQUAKES CAUSE A TSUNAMI