Karteikarten
Geography
Karten in diesem Stapel (21)
- 1IGNEOUS ROCK. . . Made of molten lava/magma (volcanic) Formed under the surface (intrusive) Magma created & cools slowly Large crystals grow Example: GraniteSEDIMENTARY ROCK. . .
Sediment = (weathered & eroded material, mineral particles: mud, sand, clay)
Sediment builds up over time, usually underwater
Pressure means water & air pushed out and this forms rock
Fossils: plant & animal remains trapped - 2METAMORPHIC ROCK. . . Tough & resistant, overcame hard conditions Changed from an earlier state PRESSURE & heat Igneous shale, clay, volc. ash = Slate Sedimentary Limestone = MarbleWHERE ARE ROCKS FOUND IN N.I.?
Basalt = Giant's Causeway, Co. Antrim
Granite = Mourne Mtns., Co. Down - 3CHARACTERISTICS OF ROCKS. . . Basalt - Dark grey/black, glittery speckles Granite - Speckled grey/white/black/pink, very hard, large crystals visible Limestone - Grey/white/yellow, fossils?, fizzes when acid is addedCHARACTERISTICS OF ROCKS (II). . .
Sandstone - Yellow/orange, often see grains of sand, may rub off
Slate - Dark grey, layers split apart easily, smooth, can be marked
Marble - White/swirls of colour, can be polished for fireplaces & floors - 4THE THEORY OF PLATE TECTONICS. . .STRUCTURE OF THE EARTH. . .
Inner Core = 5000 degrees, densest part of Earth, iron & nickel, 2200 km deep, solid
Outer Core = Liquid, 1200 km deep, i & n
Mantle = 2900 km thick, silicate rocks, 3500 degrees, AKA: asthenosphere
Crust = 5-70 km deep, some crust floats on magma, AKA: lithosphere - 5WHAT HAPPENS @ DESTRUCTIVE P.B.? This is where a CP & OP are converging, due to CCs in mantle. OP is forced under CP, into mantle, creating deep ocean trench. OP melts in the SZ created, where huge amounts of friction=EQs are felt. Magma rises through cracks in the rock & creates composite cone volcanoes (Nevada Del Ruiz) & Fold mtns. (Andes Mtns.)
- 6WHAT HAPPENS @ CONSERVATIVE P.B.? 2 plates slip past. No crust created or destroyed. Sometimes plates move in different directions, or same direction but @ different rates. Plates don't pass each other smoothly. Lots of friction between 2 plates (builds up overtime). When pressure of friction is released to let plate move, plate 'jerks' forward & momentum causes EQ. EG: San Andreas Fault Line separates N.A.P. & Pacific Plate. Both plates move forward, but N.A.P. is faster.
- 7WHAT HAPPENS @ CONSTRUCTIVE P.B.? 2 plates diverge as CCs push plates further away (Usually undersea), as they diverge, a seabed gap is created (mid-ocean ridge), filled with fresh magma from deep inside Earth. Undersea shield volcanoes form, & grow with each eruption until they break surface & form small islands. Islands can be stretched with diverging of plates (Iceland is getting bigger by 2.5 cm P.A.). Small tremors can occur.
- 8WHAT HAPPENS @ COLLISION P.B.? 2 C.Ps are forced by CCs in mantle to converge. CC can't be submerged into mantle so plates push each other upwards. EG: Indo-Australian Plate & Eurasian Plate. Battle has created an uplift of fold mtns. in the area (Himalayas). Fold mtns.=sedimentary rock, starting when rivers deposit sediment in a depression between 2 large plates (geosyncline) As more sediment is deposited on seabed, pressure is exerted & forms sed. rock. Plates converge & rock is crumpled UPWARDS to form fold mtns. When rock folds upwards, it's called an ANTICLINE, when folded downwards, it's a SYNCLINE.
- 9BASALT COLUMNS. - GIANT'S CAUSEWAY. . .Magma poured out of cracks & fissures into an ancient river valley, where it got trapped & ponded & cooled very slowly. While lava cooled, some surface areas flooded with water to form temporary lakes. Cracks also appeared on surface. Lava lost heat upwards into the atmosphere & downwards into the ground, causing hexagonal column shapes to extend many metres.LAVA PLATEAU - ANTRIM PLATEAU. . .
During the Tertiary era, outpourings of lava created the large expanse of A.P., an extrusive feature covering an area over 3900 km2 in N.E. of N.I. Lava rose to surface through long fissures (cracks in crust through which lava erupts). Many large outpourings of lava occurred, hardening into large lava plateaus made of basalt. - 10VOLCANIC PLUG - SLEMISH. . . V.P. is intrusive & formed when magma is forced up from under crust to move up a volcanic vent. Magma pours through Slemish vent as lava & swamps surrounding area in lava which hardens to basalt. As volcanic activity ends, vent is blocked by a large lump of hard magma which forms DOLERITE - harder & more resistant to erosion than basalt. Overtime, rain, ice & wind weather away softer basalt slopes of volcano, leaving harder dolerite exposed above A.P.'s flat landscapes.MARKET RASEN EQ - 27/02/08 @ 00:56
Magnitude? 5.2 on Richter Scale
Depth? 12 miles Length? 10 seconds
Causes? INTRAPLATE EQ - tectonic pressures from North Atlantic ridge & African Plate put stress on strike-slip fault line in local area. It ruptured & jolted violently, causing an EQ
Impacts? 15 small aftershocks (1-2 on R.S.), 19 year old David Bates got a fractured pelvis as his house's chimney fell on him, animals became agitated, 77 hens died in someone's chicken house. Total cost of damage = £10 million - 11EARTHQUAKE - A fault rupture that generates seismic waves. Occurs when rocks on either side of the fault cause the ground to vibrate & shake. Natural hazard FOCUS - Place where EQ originally occurs, origin of seismic energy EPICENTRE - Place on Earth's surface which is shortest distance from focus, where magnitude of energy is felt most RICHTER SCALE - A logarithmic scale used to measure the magnitude of EQSEISMOGRAPH. . .
Consists of a weight with a pen attached, which is suspended from a spring. During an EQ the base of seismometer moves horizontally & motion is converted to an electrical voltage & recorded onto paper. Amount of energy released by EQ is measured by this, can be used to find out the destructive power of the EQ.
- 12LOCATION OF MAJOR EQ. . . Most major EQs occur around Pacific Ocean, EG: Honshu EQ measuring 9.0 on R.S. occurred in Ring of Fire. They happen in zones of activity that coincide with P.B. 2 of the main belts are the Ring of Fire & Mid-Atlantic Ridge. EG: Bio-Bio EQ of 2010 in China occurred because China is on the edge of Eurasian Plate.
- 13LIQUEFACTION. . . Happens when rock/soil containing water is shaken by an EQ. Water rises to surface & turns soil to liquid mud. Any buildings resting on this sink into mud & collapse.TSUNAMI. . .
Large wave of seawater, caused by undersea EQ. Shockwaves from plate movement create small waves (30 cm high) on ocean surface. As they come into shallower water, they slow down & gain momentum (up to 30 m high). Before a tsunami, there is a dramatic fall in sea level, and water retreats back out into ocean. - 14GREAT TOHOKU EQ, JAPAN 11/03/11 @ 14:46 9.0 on Richter Scale!WHERE? Epicentre approx. 43 miles east of Tohoku, focus depth of 20 miles!
WHY? Philippine & Pacific Plates are moving towards Eurasian/North American Plate @ fairly fast rate (8 cm P.A.) A classic destructive P.B. where a subduction zone has formed as O.Ps are colliding with C.P.'s. Lots of friction built up overtime, which led to old oceanic crust being subducted, causing a megathrust EQ measuring 9.0 on R.S.! - 15SHORT-TERM IMPACTS ON PEOPLE. . . 20,350 people died; 332,395 buildings destroyed/damaged; 300 hospitals damaged & 11 destroyed; 4.4 million households without electricity (Fukushima nuclear plant flooded); houses, factories, roads, buildings destroyed due to ineffective defencesS.T. IMPACTS ON ENVIRONMENT. . .
Fore & aftershocks all measuring 6+ on R.S. Caused further tears & fissures on ground across Japan; tsunami - 40 m high only 30 mins after EQ; pollution, water supplies affected; land subsidence - coastal areas dropped by 50 cm, making them more liable to flooding - 16LONG-TERM IMPACTS ON PEOPLE. . . Cost economy $250 billion; 3 of Japan's SDF died in relief operation & 922 more died due to harsh living conditions after EQ; evacuation of 200,000 residents due to nuclear meltdown; contaminated water & food; radiation levels x8 normal level; Tohoku Expressway destroyed & Senai Airport floodedL.T. IMPACTS ON ENVIRONMENT. . .
Over 900 aftershocks (some 7+ on R.S.) - killed people, damaged elec. supplies & a nuclear plant; liquefaction - 30 homes destroyed & 1,046 buildings damaged by this process alone; landmass movement - EQ moved parts of N.E. Japan 2.4 m closer to USA, making parts of Japanese landmass wider than before; coastline movement - 250 mile stretch of coastline dropped by 0.6 m, letting tsunami travel further inland; earth axis shift - EQ shifted earth's axis between 10-25 cm, shortening day by 1.8 microseconds - 17PREDICTIONS & PRECAUTIONS BEFORE EQ EQ-proof buildings - designed to withstand EQs with springs or rubber pads to absorb shockwaves; Japan spent £70 million+ predicting EQs & use laser to measure Earth movements, but didn't believe Tohoku was in danger zone; EWS - over 1,000 seismographs; EQ & tsunami drills every 1st Sept. (anniv. of disastrous 1923 Tokyo EQ) allow emergency teams & individuals to practise & improve responses; people keep EQ kits (inc. blankets, water, rive & radio) in their homesIMMEDIATE & L-T STRATEGIES AFTER EQ...
Red Cross donated over $1 billion, 30,000 emergency relief kits & 14,000 sleeping kits in evac. centres; Red Cross reported in August 2011 52,358 prefabricated houses had been completed in 3 worst affected areas as well as 110,000 household appliance packages; temporary shelters were also built quickly by army, which helped people survive following cold nights; 23 million+ Yen would be available over next 10 years to aid rebuilding programs; new measures taken to upgrade evac. centres; 18 m high barriers built around nuclear plants; socially - festivals continued in order to boost country's morale - 18—INDIAN OCEAN EARTHQUAKE
26th DECEMBER 2004...
9.2 on Richter Scale!
- 19WHERE? Indian Ocean (also hit Thailand, Sri Lanka, India, Indonesia, Malaysia) Worst hit town = Banda Aceh, Sumatra, Indonesia (closest coastal town to epicentre)CAUSES? Major fault line in I.O., where Indian Plate converges with Burmese Plate. It's a destructive P.B. & a S.Z.; I.P.(oceanic) subducted underneath B.P. (cont.), forming a deep ocean trench (Sundra Trench); 15 m slippage along fault line happened in 2 stages. Plates moved sideways & ocean floor rose by several metres, displacing tonnes of water; hit coastal areas; death toll = 187,000+
- 20IMPACTS ON PEOPLE. . . LONG TERM: Death toll = 187,000+ (1/3 kids); emotional trauma - no bodies to bury; rebel group declared ceasefire (Indonesia) SHORT TERM: 125,000 injured; 1.1 million temporarily displaced; fishing provided employment to 1/4 of a million peopleIMPACTS ON ENVIRONMENT. . .
LONG TERM: Global sea level raised by 1 cm; mangrove & coral reefs damaged; Maldives' freshwater supply contaminated by seawater; day shortened by 2.68 microseconds
SHORT TERM: 66% of Sri Lankan fishing fleet destroyed; tsunami reached 30 m high; earth vibrated by 1 cm; aftershocks continued for 3-4 months - 21PREDICTIONS & PRECAUTIONS BEFORE EQ... There weren't any EWS to record underwater EQs within I.O. Simeulue evacuated coastal areas because people felt tremor & fled to inland hills. In Phuket (Thailand), a girl recognised signs of tsunami & saved many lives. KNOW WARNING SIGNS OF A TSUNAMI. The area affected lacks expensive resources for predicting EQs.STRATEGIES & RESPONSES...
Over US $7 billion were donated from nationals & NGOs. Sri Lanka, Indonesia & Maldives declared a state of emergency to allow strict laws to be introduced & help with humanitarian aid distribution. 25 new seismographic stations were set up by UNESCO