TECTONIC & COASTAL SYSTEMS

Question 1

Assess the extent to which volcanic activity (VE) can influence Coastal Landforms

Answer 1

Volcanic Activity - eruption of molton lava, rock, gases from a volcano
Can be explosive or effusive or can create lava flows.

Coastal LAndscape System - Dynamic systems shaped by the interaction of physical orocesses and human interactions. Coastal landscapes include landforms such as beaches, cliffs, dunes, deltas, headlands,

Can depend on type of eruption and type of landscape

1. Creation or Destruction of Landforms

Creation (usually caused by effusive eruotions and release of balsatic lava)
VE –> new land eg lava deltas or volcanic islands
Eg Hawaii - volcanic islands created by volcanic hot spots

Destruction - using explosiove send rocks & ash high into atmosphere
Mount St Helens
Landslide into Spirit Lake –> raised lake levels.

2. Erosion & Deposiition
   Volcanic materials. such as rock and are eroded and deposited –> unique features
   Black sand beaches eg Iceland
3. Tsunamis
   Under water eruptions –> Tsunamis
   Can severely damage coastlines
   Human interventions eg sea walls can impact coastal systems by preventing erosional damage
4. Influence on coastal ecosystems
   EG E15 damaged marine ecosystems –> damaged fish habitat–> destroyed fishing employment —> changes how used & managed
5. Sea Level Changes
   Volcanic eruptions can have big impact on climate –> changes __> sea level rise or fall—> emergent or submergent landforms.
   Short term Eg Mount Pinatubu Philippines 1991 –> fall 0.5 degrees –> sea levels dropped
   Long term –> CO2–> increase in temp–> increase in sea levels

Conclusion
VE can have significant impacts however extent of impacts, the time scale, the nature of volcanic activity & soecific characteritics of coastal landscape determines how great the impact is.

Question 2

Assess the extent to which earthquake activity (VE) can influence Coastal Landforms

Answer 2

Seismic activity (EQ) = frequency and magnitude of earthquakes at a specific time in a specifica rea.

Coastal Landscape system = dynamic systems shaped by interaction of physical coastal processes and human activitoes.

1. EQs cause Tsunamis–> landform changes (subduction of plate boundaries )
   Eg 2004 Indian Ocean earthquake
   Tsnumai caused widespread erosion & deposition across 14 different countries
2. Land Elevation changes (tectonic uplift or downthrust)
   EQ activity can lead to elevation changes –> emergent or submergent landforms
   Eg Alska (1964) land elevated –> escarpments
   Eg Nepal Earthquake 2015
   Slopes eroded by mass movement landslides
3. Landslides
   Nepal Earthquake 2015
   Landslides–> reshaped land, buried villages & changed flow of rivers–> sea
4. Sediment Liquification
   Release additional sediment into coastal landscape system —> depositional landforms
   Eg Christchurch NZ—> sediment deposition along coast –> dunes & beaches
5. Affects Human Activities at Coast
   Destroy beaches for tourism
   Eg Indian Ocean Tsunami
6. Seismic Sea Waves “seiches”
   Lead to flooding of coastal areas–> increased erosion
   —> creation of sea walls to protect

Question 3

How do Tectonic Processes affect the formation & evolution of coastal landscapes

Answer 3

Tectonic Processes are: Plate tectonics (earth’s outer shell divided into several plates which glide over the mantle) , seafloor spreading (new ocean crust created at ridges by volcanic activity) , rifting (lithosphere pulled apart–> rift valleys s and eventually ocean basins ) , subduction (edge of one plate slides under another–> EQ & VI) , OROGENY (folding & faulting of Earth’s crust) , conservative transform boundaries (plates slide past each other–> EQ) .

Tectonic processes significantly influence the formation and evolution of coastal landscapes.

1. Creation of Oceanic Crust (Seafloor Spreading): At divergent plate boundaries, such as mid-ocean ridges, new oceanic crust is formed This can lead to the creation of new landforms at the coast, such as rift valleys and volcanic islands1.
2. Destruction of Oceanic Crust (Subduction): At convergent plate boundaries, one tectonic plate subducts or slides under another. This can lead to the formation of various coastal landforms, including volcanic arcs and deep-sea trenches.
3. Tectonic Uplift and Downthrust: Tectonic activity can cause land to be shifted upwards (uplift) or downwards (downthrust), leading to changes in relative sea level. This can result in the formation or alteration of various coastal features, such as cliffs, beaches, and estuaries. Eg submergemnt/emergent landforms.
4. Influence on Coastal Geology: The geological structure and rock type (lithology) of a region, which are influenced by tectonic processes, can significantly affect the shape and form of the coastline. For example, discordant coastlines, where rock structures meet the coast at an angle, can lead to the formation of headlands and bays. Conversely, concordant coastlines, where rock structures run parallel to the coast, can lead to the formation of coves and lagoons.
5. Earthquakes: Tectonic activity can also cause earthquakes, which can trigger tsunamis and lead to significant changes in coastal landscapes12345. Eg coastal erosion
   In summary, tectonic processes play a crucial role in shaping coastal landscapes by influencing the formation and alteration of various coastal landforms.

Question 4

Examine how earthquake and volcanic activity might influence the flows of energy and material through a coastal landscape system.

Answer 4

Seismic activity (EQ) = frequency and magnitude of earthquakes at a specific time in a specific area.

Volcanic Activity = Volcanic Activity - eruption of molton lava, rock, gases from a volcano
Can be explosive or effusive or can create lava flows.

Coastal Landscape system = dynamic systems shaped by interaction of physical coastal processes and human activities.

Volcanic Activity

Ash–> increased sediment (input)
Eg Christchurch New Zealand

Lava Deltas–> impacts currents and distribution of wave energy–> change in erosional and depositional processes which impacts flows and landforms

Glacier Melt
Volcanic activity increases waters stores in soil and in rivers –> increases ocean stores
Eg E15

Changing water levels (seas & lakes)
Mount St Helens landslide–> rose level of water in lake—> submergent processes

Earthquake Activity

Land Elevation
Alaska Earthquake 1964 - uplifted areas subject to erosional processes eg chemical weathering –> increase sediment load
or new areas exposed to wave preocesses

Land Destruction/Alteration
Tsunamis can erode/destroy beaches and cliffs and can transport vast amount sof sediment creating new landforms
Eg Indian Ocean Earthquake 2004

Landslides
Earthquakes cause landslides –> movement in sediment load into river systems–> affect coast.
Eg Nepal 2015

Liquification
EQs –> liquification of soil –> shifts vast amount of sediment.
Eg New Zealand

Question 5

How are tectonic hazards linked to emergent and submergent landscapes

Answer 5

Emergent coasts

1. Tectonic Uplift (isostatic Uplift)
   NW America coast is an emergent coastline due to its proximity to an active plate tectonic margin.

Sweden & Norway & Scottish highlands coastlines have experienced uplift due to glacial melt–> reduced weight –> lift

2. Submergent Coast & tectonic Subsidence
   Often seen in land ADJACENT to areas experiencing isostatic uplift.
   eg Western Norway
   Coastal landscapes flooded by ocean water due to elevation in sea levels.
   Caused by increase in ocean volume or increase in land mass—> sinking
3. Impact of EQ
   Changes in elevation of sea bed - faulting up or down
   Eg Alaska
4. Impact of Volcanos
   Landform creation eg volcanic chains and sea floor spreading can increase or decrease displacement of ocean water –> water level rise or fall

Volcanoes emit C02—> greenhouse gas –> climate change–> glacial melt –> increase in sea levels (less dense–> vol increase)
Volcanoes emit ash–> climate cooling —> decrease in seal levels ( dense–> vol decrease)
Eg Mount Pinatubu

Question 6

How is Human Activity influenced by Tectonic Hazards in coastal landscapes

Answer 6

Human activity can include

Strategies to change coastal landscape with a view to protecting it.
Protection against flood ing caused by seiche and tsunamis via hard & soft strategies
Eg sea walls, groynes, riprap, reef barriers
Eg Japan constructed 400km wall on NE coastline to give residents time to evacuate.
Eg New Zealand & Japan

Economic/Industrial /Agricultural activities
Tsnumais can destroy land, infrastructure & livelihoods
Eg destroy fishing industry eg Tohoku japam 2011
eg 2004 Indian Ocean tsunami
–> Tourism - destroyed beaches eg Sri Lanka & Thailand
–> Agriculture- Farm land destroyed due to salt water contamination
eg 2004 Indian Ocean tsunami
Leisure Activities

Social Activities (living, school, healthcare etc)
Housing On Chile coast destroyed by 2005 earthquake.

Question 7

How does tectonic activity influence coastal landforms?

Answer 7

Tectonic Activity = movement of Earth’s crist which is made of continental and oceanic plates. They meet at plate boundaries. Tectonic activity can lead to volcanic activity, mountain building, trench formation, earthquakes, uplifting and downthrust and horizontal displacements along faults.

Influences coastal landforms:

1. formation of cliffs and lagoons
   Tectonic uplift –> cliffs
   Sinking–> lagoons
2. Rifting –> Changes in sea level–> submergemt or emergent landforms
   Rifting at divergent plate boundaries–> change shape of ocean basins–> effects sea levels.
3. Volcanic Activity
   Creation of landforms & sea level changes
   Hot Spot–> Volcanic Islnd Chains
   eg lava plateaus
   —> displacement of sea water–> affects levels
4. Earthquakes—> changes in sea bed elevation –> change sin sea levels
   Eg Alaska Earthquake
5. Sediment Load Increase–> increase in depositional processes eg transporttation —> depositional landforms in new places
6. Increase erosion due to ash paricles in water-__> Increase in erosional processes eg attruition–> increase in erosional landforms eg headlands & Bays