Australias Coastal Problems

In comparison with many countries of the world, Australia possesses an enormous continuous coastline. Including islands, Australia's coast stretches for about 60 000 kilometres and comprises over 10 000 separate beaches. About two-thirds of the population live in the towns and cities that have been built to take advantage of the many benefits the coastline brings. Coastal management refers to the use and protection of this vast area, which is made up of marine (saltwater) and estuarine (meeting point of fresh and saltwater) ecosystems. In a constant state of evolution, these areas are naturally affected by rainfall, wind, ocean currents, waves and tidal movements.

The construction of houses around lagoons and swamps, the use of wetlands for landfills and the development of sand dunes for 'prime' real estate and recreational purposes have all had negative effects on Australia's coastal areas. The removal of vegetation has seen a significant reduction in biodiversity and also disrupted the natural processes which form intricate coastal ecosystems.

Beaches, for example, are formed by an ongoing cycle of erosion and deposition of sand. Storms erode beaches of their sand, which is then re-deposited by large waves. When humans attempt to use these areas for housing and recreation, this natural cycle is interrupted and sand banks become depleted. Over time, this has destroyed many of Australia's beautiful beaches. Cliff-top housing, although aesthetically pleasing for home-owners, is also dangerous because of its interference with these natural processes

Vast areas of land covered in concrete and bitumen, particularly in large cities, generate an enormous amount of contaminated stormwater and rainwater run-off. This pollutes our waterways and damages fragile coastal ecosystems. Added to these contaminants are petroleum-related pollutants emitted from motorboats, ferries and large ships, which account for about 20-30 per cent per cent of all marine pollution

One factor which has hindered the protection of Australia's coastline in the past has been a lack of tight regulations placed on private sector developers. Another is that different levels of government in Australia manage separate areas of the coastline. Broadly speaking, responsibility for the coastline within three nautical miles (nm) of the shore rests with the local, State and Territory governments. The federal government is responsible for the management of waters for 200 nm beyond this. This division of powers can complicate matters because the environmental impacts of activities undertaken in coastal zones do not follow this jurisdictional division.

On a positive note, in 2003 the federal government endorsed the 'Framework for a National Cooperative Approach to Integrated Coastal Zone Management'. This initiative has been a key milestone in addressing the need for coordinated efforts and tighter monitoring of development in the area of coastal management.

Sources:'

http://www.environment.gov.au/science/soe/2011-report/11-coasts/2-major-issues

http://www.ozcoasts.gov.au/indicators/beach_erosion.jsp

http://wwf.panda.org/who_we_are/wwf_offices/australia/environmental_problems_in_australia/

Australian Cyclone & Tornados

The Australian cyclone season officially runs from November to April, although very few have occurred in November. The earliest cyclone to impact the northwest coast in a season was on 19 November 1910 when the eye passed over Broome. The latest cyclone was Herbie that formed near Cocos Islands and passed over Shark Bay on 21 May 1988. At the start of the cyclone season, the most likely area to be affected by tropical cyclones is the Kimberley and Pilbara coastline. Later in the season, the area threatened extends further south including the west coast. The chance of experiencing an intense category 4 or 5 cyclone is highest in March and April. Australia government in addition to having buoys in the ocean has a tropical cyclone warning services online that cover these areas,

• ·         Tropical cyclone seasonal outlook
• ·         Tropical cyclone outlook
• ·         Tropical cyclone information bulletin
• ·         Tropical cyclone watch
• ·         Tropical cyclone warning
• ·         Technical summary
• ·         Tropical cyclone forecast track map
• ·         Marine warnings

Tracks of cyclones in the Australian region from 1989/90 to 2002/03

A recent series of destructive tornadoes in Queensland, New South Wales and Victoria have shattered the myth the violent storms don't strike Australia. A review of Bureau of Meteorology data by Fairfax Regional Media has also shattered that commonly-held perception. The data, which charts recorded tornadoes between 1795 and 2012, shows more than 1200 tornadoes have killed 28 people, injured dozens and destroyed hundreds of homes and businesses. Australia has just recently just implemented a tornado warning system in its most recent hit areas. The area is also known for fire tornados. Which when the condition are just right this phenomenon happen creating an amazing spectacle.

Sources:

http://www.bom.gov.au/cyclone/about/warnings/advice.shtml

http://www.naa.gov.au/collection/fact-sheets/fs90.aspx

Australian Sinkholes

In the last year alone they have caused houses, apartment blocks, roads and even a sleeping man, to disappear into the ground without warning – and every year there are more destructive sinkholes than ever before. Mount Gambier is one of a very small handful of places in the world with the soft limestone bedrock that creates deep, circular, spectacular sinkholes like the ones found in Mexico and Florida. 

Beneath the regional center of Mount Gambier is a myriad of caves. According to Aussie geologist and sinkhole buff, Ian Lewis, the only things keeping them from collapsing are the dry conditions and relatively stable water table.In addition to southern Australia’s Limestone Coast, the northern suburbs of Perth, parts of Canberra, Newcastle, the Nullarbor Plain and western NSW have have seen sinkholes appear in recent years.Australia’s largest sinkhole has a lake at its floor and it is a popular tourist attraction, but our diving expedition to the bottom of two at Ewen's Ponds and Piccaninnie Ponds, which no one has ever been to the bottom of, revealed the caves that could be the next sinkholes waiting to happen. Preventing Sinks holes by Redirecting or Blocking Water,Treating Underground Limestone, Construction Measures, Avoid Construction on Wetlands, Seawater Treatment Facilities, Recycling Grey Water Run-off.

Humans do contribute to sinkholes and probably have ever since the invention of irrigation. Anything that has the potential to divert water into weak points beneath the earth will accelerate the creation of the pits into which houses, cars and unfortunately people sometimes fall. The drying out of the ground by abstraction or the soaking from a burst pipe are the most direct examples of human-caused sinkholes.

Sources:

http://www.theaustralian.com.au/news/the-season-for-sinkholes/story-e6frg6n6-1226597176224

http://www.smh.com.au/environment/sinkhole-swallows-southeast-queensland-beach-20110626-1gm67.html

Australian Mass Wasting

In Australia, 114 landslides are known to have caused injury or death during the period 1842 to December 2011. At least 138 people have been killed and 174 injured. The naturally-occurring events causing death varied from the fall of a single rock to spectacular debris flows and their flash flood run outs. Many landslides that killed or injured people were the result of human activity. During the period 2000-2011, over half the landslides causing injury or death were directly or indirectly human-caused. Most deaths were caused by trench and beach sand or excavation cave-ins, while most injuries were caused by edge-of-road collapses due to vehicle weight.
On 22 March 2010, intense rain brought by a severe storm triggered a debris flow from the escarpment at Kings Park, Perth, Western Australia, behind the Adelphi, Waldorf, Acacia and Park Lane apartments, causing more than 100 residents to be evacuated. Mud surrounded two vehicles and entered apartments through the windows, filling two with mud deeper than 1.2 meters. A section of the eastbound lane of Mounts Road was also closed.

What Australia is doing to prevent Landslides

• Capture and drainage of water before it reaches potential slope area
• Underground drainage by using sub-surface pipes
• Land Reform by terracing/re-shaping
• Reforestation, planting of deep rooting trees to prevent surface slips
• Ground cover with grass or agricultural crops
• Use of Gabion construction to protect water course valleys and control the flow of water down slope

Australian Tsunami

Tsunami is a Japanese word - tsu meaning 'harbor' and nami meaning 'wave'. It was coined several hundred years ago by fishermen who came back from sea to discover the harbor devastated by waves, even though there had been no wind and no unusual wave action observed in the open ocean.

 Unlike wind-generated waves which cause movement of water near the sea surface, tsunami are waves generated by sudden movement of the sea floor, mostly by undersea earthquakes which cause the entire overlying water column to move vertically. The resulting wave spreads outwards from the source and has wavelengths of 100 kilometers or more. Submarine landslides and, less frequently, a volcano or meteorite impact also can cause tsunami. Although such impacts are rare, it has been suggested that tsunami generated by meteorites or comets may have reached Australian shores in prehistoric times

In Australia, public advice on any tsunami threat is being provided by the Bureau of Meteorology and Geo science Australia. The agencies continue to establish extensive networks of seismic and sea level monitoring instruments which are being integrated with sophisticated computer systems designed to detect and forecast the arrival of tsunami. However, because of the proximity of Australia to known earthquake zones off Indonesia and between New Guinea and New Zealand, the travel time for a tsunami from the nearest danger zones is around three to four hours. This provides some limited time to analyse the potential threat and issue warnings. For countries closer to an earthquake source, a tsunami may arrive in less than 15 minutes, allowing limited time for warnings to be issued. On 26 December 2004, strong currents and sea level variations were observed along Australia's west and southern coasts with around 35 people being washed out to sea and subsequently rescued.
           
While the overall risk from tsunami to the Australian population is lower than it is for many parts of the world, some preliminary assessments by the Australian Government indicate that the north-west and east coast have the potential to be affected by a damaging tsunami resulting from a large earthquake. A recent relatively significant event was the 17 July 2006 Java tsunami, which achieved a run-up height of eight meters above sea level on isolated sections of the Western Australian coast. Although earthquakes are seen as the most likely source for tsunami in the region, there are at least five active volcanic source regions capable of generating tsunami which could affect Australia

REFERENCES

Bryant E, (2001) Tsunami: The Underrated Hazard,

Dominey-Howes D, Marine Geology, 239 (1), pp. 99-123, April 2007

Rynn J and Davidson J, (1999) ‘Contemporary assessment of tsunami risk and implications for early warnings for Australia and its island territories’, Science of Tsunami Hazards, 17(2):107-125

Australias volcanic activity

There has not been any eruptions in Australia in this century. The most recent eruption in Australia was at Mt. Gambier, a shield volcano in the Newer Volcanic Province, Victoria. The Newer Volcanics Province in Victoria Australia is made of four shield volcanoes and associated vents: Red Rock, Mt. Napier, Mt. Schank, and Mt. Gambier. They last erupted between 5850 and 2900 B.C. The eruptions were explosive and some generated lava flows. It is impossible to say if the volcanoes will erupt again. However, there have been rare earthquakes in the area, most recently in 1976. There are numerous volcanic islands north and east of Australia including North Island, New Zealand, the islands of Vanuatu, the Solomon Islands, New Britian, and Indonesia. There are numerous interesting volcanic provinces in Australia. There are flood basalts of Cambrian age (about 650 million years old) northeast of Halls Crossing in northern Australia. Volcanism commenced about 70 million years ago at volcanic centers in southeast Queensland and northeast South Wales. Compositions range from basalt to rhyolite and includes shields, plugs, and domes. In north Queensland there are some very long basaltic lava flows. For example, at Undara a flow is 100 miles (160 km) long.

Geo science Australia monitors seismic data from more than 60 stations on the Australian National Seismograph Network and in excess of 300 stations worldwide in near real-time, 24 hours a day, seven days a week. Most of the 40 samples per second data are delivered within 30 seconds of being recorded at the seismometer to Geo science Australia’s central processing facility in Canberra through various digital satellite and broadband communication systems. This allow the government the ability to give advanced warnings of potential eruptions.

Sources of Information:
Johnson, R.W., 1976, Volcanism in Australia: Elsevier, New York, 405 p.

Johnson, R.W., Knutson, J., and Taylor, S.R., 1989, Intraplate volcanism in eastern Australia and New Zealand: Cambridge University Press, Cambridge, England, 408 p.

Simkin, T., and Siebert, L., 1994, Volcanoes of the world: Geoscience Press, Tucson, Arizona, 349 p.

Australia seismicity

The Earth is a dynamic planet consisting of an outer crust riding on so called lithospheric plates that are roughly 100 km in thickness. Australia lies within one of these plates. The lithospheric plates move relative to one another at rates that are typically around several cm per year. In some places, oceanic plates are gradually plunging into the Earth's mantle such as under Japan and Chile whereas at mid-ocean ridges, new crust forms as the plates move apart. It is the movement of the lithospheric plates that induces stresses in the crust and causes mountains and faults to be created both at plate margins and within plates. The Australian plate has been subjected to enough stress for mountain ranges to have formed and the present stresses are sufficient for earthquakes to occur.



On 28 December 1989, an earthquake measuring 5.6 on the Richter scale hit Newcastle. The epicenter was 15 km south-southwest from the city center. This earthquake caused widespread damage, damaging 50 000 buildings and killing 13 people. Damages are estimated to have cost $1.5 billion. The death toll from the earthquake could have been a lot worst. Fortunately, school was not in session at the time, as many schools were badly damaged.Although 5.6 is generally considered to be only a moderately strong earthquake, many buildings were destroyed. This was due to a number of factors. Newcastle was considered to have a low seismic risk, so buildings were not expected to adhere to earthquake standards. Many of the damaged buildings were built on alluvial land, or land deposited by water, which is affected more strongly by earthquake waves. The shaking went on for a very long time, 35-40 seconds. Finally, the focus was very shallow at only 11 km below the surface of the Earth. While the earthquake's measurement on the Richter scale was moderate, its measurement on the Mercalli scale would have been much higher.This paved the way for new building codes and tighter enforcement. 





Sources: http://en.wikipedia.org/wiki/Queensland
http://www.ses.sa.gov.au/site/community_safety/earthquake_information.jsp
http://www.seismicity.see.uwa.edu.au/welcome/seismicity_in_australia