Volcanic Hazards

Question 1

What are the 3 types of landforms?

Answer 1

continental continental
Continental oceanic
oceanic oceanic

Question 2

What is an example of oceanic continental landform?

Answer 2

Deep sea Trench (Peru-Chilli Trench in Pacific Ocean)

Question 3

What is an example of continental continental landform?

Answer 3

Fold Mountains (Himalayas in Asia)

Question 4

What is an example of an oceanic oceanic landform?

Answer 4

Deep sea trench - island Arc (Mariana Islands in the North Pacific ocean)

Question 5

What are the 3 types of plate margins?

Answer 5

Constructive
Destructive
Conservative

Question 6

What is the description of the constructive plate margin?

Answer 6

Plates are moving apart (Northern American plate parting from the Eurasian)

Question 7

What are the two different landforms found on the conservative plate margin?

Answer 7

Oceanic ridge (North American Plate and Eurasian Plate)
Rift Valley (East African Rift Valley)

Question 8

Describe the movement and process of a oceanic ridge?

Answer 8

• Where diverging plates are underwater an ocean ridge forms

- Underwater volcanoes erupt along the mid ocean ridge and they can build up to be sea level (iceland)

Question 9

What is the movement and process of a rift valley?

Answer 9

• When plates diverge between land, rising magma causes the continental crust to bulge and fracture, forming fault lines.
• As these plates keep moving apart, the crust between the parallel faults drop down to form a rift valley.
• Volcanoes are found beneath rift valleys. For example Mount Kilimanjaro and Mount Kenya.

Question 10

What is the description of a destructive plate?

Answer 10

Plates moving together

Question 11

What are the 3 landforms found on a destructive plate margin?

Answer 11

Oceanic oceanic
continental continental
oceanic continental

Question 12

What is the description of a conservative plate?

Answer 12

Plates sliding together

Question 13

What is the process of a conservative plate margin?

Answer 13

1) Conservative margins occur when 2 plates are moving plates each other
2) 2 plates get locked into place and pressure builds up
3) Causing the plates to jerk past one another and crack forming fault lines
4) Releasing energy creating an earthquake
5) Many earthquakes occur along this margin and along its fault lines (San Andreas Fault California)

Question 14

What are the 2 types of volcanoes?

Answer 14

hawaiian eruption and plinian eruption

Question 15

What are some characteristics of a hawaiian eruption?

Answer 15

• Are effusive (lava flows steadily out of a volcano) and produces Basalt lava which have relatively high temperatures between 1100 degrees celsius and 1250 degrees celsius.
• basalt lava also have low silica content (less than 52% which means that lava fluid can flow long distances over 20km and at speeds of 50 km/h

Question 16

What are some characteristics about the plinian volcanoes?

Answer 16

• Much more explosive and produce Andesitic and rhyolitic lavas.
• These lavas have lower temperatures (600-1000 degrees celsius) and have a higher silica content ( in rhyolites typically 69%)
• This means lava is more viscous, flows more slowly and builds up in the vent until it is suddenly released into an unpredictable and explosive eruption.
• Lava flows tend to be more of a threat to property than to human life. However, when large quantities of lava are released at once, they can be increasingly dangerously.

Question 17

What is the VEI?

Answer 17

Volcanic Explosivity Index
- The volcanic explosivity index is used to measure volcanic power
- Each interval on the scale represents a ten fold increase in the eruption criteria below;
VOLUME = of ejecta (Ash and volcanic Bombs)
HEIGHT = Of the eruption column (these reached)
DURATION = Of the eruption
- Modern humans have never experienced a VEI of 7-8.