WTG - Chapter 6, Chapter 7 Flashcards Preview

Natural Hazards > WTG - Chapter 6, Chapter 7 > Flashcards

Flashcards in WTG - Chapter 6, Chapter 7 Deck (4)
Loading flashcards...
1

1. Describe the Zanclean Flood

The Zanclean flood refers to an event that occurred 5.3 million years ago (towards the end of the Miocene Epoch), whereby the Atlantic burst through the Straight of Gibraltar, filling the Mediterranean basin.

The basin had previously (a quarter of a million years earlier) been isolated from water by tectonic forces and subject to a dry and hot climate - eventually becoming a vast, desiccated empty hole 2.5 km below sea level.


Tectonic subsidence, potentially facilitated by rising sea levels and erosion, finally allowed the Atlantic to flood into the empty basin at a rapid rate.


The Mediterranean seas is estimated to have risen by as much as 10m daily over a period of 24 months.

2

2. What effect will sea level rise have on the earthquake hazard here on the west coast of British Columbia

As sea level rises more weight will be added to the coast, potentially affecting stress that continues to build up at this plate margin. This change in stress may cause:

- fewer earthquakes to happen.

- larger earthquakes to happen

- earthquake activity may location.

3

1. If a worse possible scenario takes place and the Earth's atmosphere warms significantly, how might this affect the frequency and magnitude of potentially catastrophic geological events such as volcanoes, earthquakes and landslides?

Climate change will cause a significant increase in sea levels and and extreme weather events such as storms.

This means there will be more sudden shifts of water and more weight bearing down on coastal areas.

Both scenarios suggest an increase in the frequency, size and duration of events as large masses of water are moved on the Earth's surface.

Shifting masses (water) of this magnitude can change the behaviour of volcanoes, earthquakes and landslides.

The change could contribute to an increase in frequency and magnitude.

4

20. How does the crest of a flood behave over time.

Often, in a single drainage system, the maximum discharge (Q) will travel downstream through the system

This maximum Q will occur later downstream, meaning floods travel downstream.