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Teacher blog who did it with his class:
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Wikipedia on Acid Rain

Were the floods in 2012 avoidable?

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Weather forecast presentation

Impacts of tornadoes

Impacts of tornadoes

A tornado is one of the most intense and destructive wind found on the Earth’s surface. Due to the fact that they as most common to form along a cold front mean that they can, and regularly do form in groups over wide areas. They are very destructive because the funnel wall has a very large lifting force. A large tornado has the ability to move large objects weighing as much as 300 tonnes tens of metres and can move large houses hundreds of metres. As well as being able to move large objects, tornadoes have the ability to suck up vast quantities of water. In the past, tornadoes have been seen to completely drain rivers and completely exposing the bed.
But this is not the most destructive part of a tornado. Explosions inside the tornado occur due to a large dip in pressure that happens in a very short time period. Buildings with higher air pressure’s to that of the tornadoes cause the explosion. When the high pressure is unable to escape fast enough, a large explosion is created, these explosions also produce vast amounts of heat, which can actually be the main cause of death through severe burning.

Tornadoes alone killed over 12,000 people between 1916 and 2000. Although now there is on average 200 less deaths a decade due to warning and awareness. In 1927 a town of 1200 was wiped out in under 90 seconds with 26% of the population being either dead or severely injured. Although now death toll has reduced, costs of repairs are still large. In 1974 315 people were killed in a 16 hour period between Alabama and Canada but caused damages which cost $500millionUSD.

+National Geographic +Geology +USGS Earthquake Notification BOT +Earthquake Update +Plate Tectonic

Resources used

• Environmental Hazards-Assessing risk and reducing disaster (Fifth edition) Keith Smith and David N. Petley
• Natural Hazards (Second Edition) Edward Bryant

Climatic Hazards: Tornadoes

What is a Tornadoe?

A tornado is atmospheric storm which consists of rotating column of air which extends down from cumulonimbus cloud (thunder storm cloud). They are usually only small in size and only last for a short period of time. They are often linked with supercell thunder storms.

How are Tornadoes formed?

They form because of the interaction between warm air and cold air. They are always formed over ground as the heat from the ground warms the air making it unstable through the day so that it rises. When it rises forms a cumulonibus cloud which coverges with the colder air. The air is then deflected by the Coriolis force and it spins upwards. This rotation is then aided by the differing wind speeds and direction at differnet altitudes. Supercell Thunderstorms are best at creating tornadoes due to there strong upward movement and imense downdraught. Near the rear of the storm a funnel of air can begin to appear which can lower and touch the ground forming the tornado.

Where do tornadoes appear? 

They are mostly seen in the middle latitudes but can also be linked with the updraught created by large hurricanes. The USA is one of the most common places for tornadoes to form with over 75% of the worlds recorded tornadoes being in this area. This is due to  the interaction between the warm air from the south over the Gulf of Mexico meeting with the colder air from the Arctic making perfect conditions for the formation of tornadoes. They have become so common in the southward stretch between Nebraska and Texas that the area has been named "Tornadoe Alley".

What effect do Tornadoes have?

Damage caused by tornadoes is often due to the high wind speeds which can reach over 500km per hour. There is also the lifting force of the funnel whcih can move large objects. They also create large preasure differential between the outside of buildings and there inside which can lead to them exploding outwards creating large ammouts of debriswhich does large ammounts of damge as it is blown around.

Sources:
Acces to geography - Hazards - by Malcolm Skinner (pages48 to 51)
Natural Hazards - by Edward Bryant (pages 93 - 96)

The hazards posed and some causes of tropical storms.

 I spent a large proportion of time in vein, but in the end I managed to scrounge these little gems from two academic journals published in 1994 and in 1991. Some quite interesting stuff here:

Types and causes of tropical storms:

The largest and most common type of tropical storm is the temperate or mid-latitude cyclone that forms as a result of rising air motion induced by waves in the jet stream. These low pressure systems derive their energy from the strong horizontal temperature gradients and are called "cold core" cyclones by meteorologists. Mid-latitude cyclones are the familiar low pressure regions that produce the majority of the cool season precipitation. In most of these cyclones, the pressure gradient between the centre and the outer margins of the systems is modest, averaging about 5 mb/100 km. Consequently, the associated wind fields are relatively weak, ranging from 20 to 30 kmh

However, there are times when the inducing factors, such as the presence of a substantial temperature contrast as the cyclones cross the Gulf Stream, or a sharp difference in temperature between land and the ocean, can combine to produce very strong temperate cyclones off the mid Atlantic coast. Tropical cyclones and their mid-latitude counterparts bear little resemblance apart from their cyclonic winds. Tropical cyclones are warm-core systems, in that the air temperatures at their centers are higher than those in the surrounding regions.

These cyclones form over the open ocean and get their energy from the evaporation of warm ocean water. The low pressure centre of a hurricane is augmented and strengthened in part by a massive ring of thunderstorms which release enormous amounts of heat into the storm system. The most powerful hurricanes will commonly have a 20 mb/100 km pressure gradient, which results in more powerful wind field.

The strongest winds are usually concentrated over a much smaller area than those associated with a mid-latitude cyclone. Also rather interestingly, less than five percent of all tropical disturbances develop into hurricanes. Seems bizarre but understandable from the explanation.

Coastal Storm Hazards. Robert Dolan and Robert E. Davis. Journal of Coastal Research, Special Issue No. 12. COASTAL HAZARDS: PERCEPTION,SUSCEPTIBILITY AND MITIGATION (1994), pp. 105 Coastal Education & Research Foundation, Inc.

Hazards associated with tropical storms in the mid-Atlantic region specifically:
One topic simply wasn't enough for me; I couldn't contain myself and I stumbled across this which seems quite self-explanatory but it's not the sort of thing I think about when I'm day dreaming. But apparently it is not the wind fields associated with tropical and extratropical storms that represent the most serious hazard, but rather the waves and storm surges that the winds produce. Sooner or later, all waves produced by these storms end up dissipating most of their potential and kinetic energy in the coastal zone. The growth of waves in a storm from the initial ripples and wavelets is governed by three factors: the wind speed, its duration, and the distance (fetch) of water surface over which it blows. With an increase in any of these factors, the height of the waves and the potential storm surge in creases. Wave hindcasting methods and storm surge predictions were developed by extension of the basic physics of wave generation. Wave heights generated by hurricanes typically range from 5 m to 15 m

Temporal Variation of Tropical Cyclones in the North Atlantic Basin. Anthony J. Vega and Mark S. Binkley. GeoJournal, Vol. 23, No. 4, Caribbean Hurricanes (April 1991), pp. 313 Springer

Cyclones/Hurricanes 

Cyclones cause huge damage every year, with loss of life and considerable damage to buildings as well. They normally happen around the Indian ocean, however can happen anywhere where the conditions are right.  They are usually caused by several triggers, 1) warm or moist air, 2) wind blowing in different directions 3) Low wind, known as low wind shear 4) sufficient distance from the equator causing spinning. 

They are low pressure systems over the tropics or sub tropics with organised convention. They are normally 5/6 miles high and 300/400m wide. They are normally about 10-15mph, however can be more. Anything above wind speeds of 74mph are considered to be hurricanes. Hurricanes are large cyclones. 

 Predicting cyclones is very difficult, often predictions from the sea are used, however, predicting them is considered a fine skill. Prediction is also done by people at specialist tropical cyclone forecasting centres around the globe such as the National Hurricane Center in Miami, Florida who are constantly studying satellite images, instruments and other weather data to detect and track them through their life-cycle.

Notable cyclones that you may have heard of Katrina - 2005 - Katrina was the most costly hurricane on record causing an estimated $75 billion in damage in Louisiana and Mississippi. 

HW

Tornadoes!

Definition: A mobile,destructive vortex of violently rotating winds having the appearance of a funnel-shaped cloud & advancing beneath a large storm system.

Causes:
Formation is precipitated by warm moist air near the ground meeting cold, dry air. Tornadoes usually form over land but they can form over tropical oceans. When the ground is heated by the sun, warm moist air rises. As it rises it cools forming massive cumulonimbus clouds and releasing heat that sustains the updraft. The updraft meets winds of different directions and speeds. This together with the rotation of the earth causes it to spiral coutnerclockwise, creating a vortex. The strength of the updraft determines how much of the surrounding air is sucked into the bottom of the tornado. As it rises the jet stream takes effect and causes an extra spin and the characteristic anvil cloud.

Measuring:
There are two ways that Tornadoes are measured: 1)The Fujita Scale and 2) Pearson Scale,
The Fujita scale is based on the speed of the tornado, whereas the Pearson Scale is based on the length and width of the tornado path.

Tornado Alley:
Tornado Alley in the USA has the perfect conditions for the formation of tornadoes. This is due to a number of factors. The first being there is a plentiful supply of warm moist air being brought in by the low level winds from the south and the Gulf of Mexico. The second is the very dry air that comes from the Rocky Mountains and the deserts of northern Mexico. The third is the prevailing westerly winds sometimes accompanied by the powerful jet stream, carrying cool air from the Pacific Ocean.

References:
Stormy Weather by Mark Maslin p30-33.
Hazards by Malcolm Skinner p48-49

Introduction Into Tropical Storms

A basic definition to start - Tropical Cyclone - Violent tropical storms between 200-700km in diameter with very strong winds circling a calm eye. (1)

Conditions needed - Sea temperatures to be 26 C and above. Depth of ocean at 70m. Location of 5 N/S of equator for the Coriolis* effect to take place. Low level of convergence of air in low atmosphere. Rapid outflow of air in upper atmospheric circulation. (1)

Occurrence - Latitude of 5 degrees to 20 degrees N/S of equator. Moves Westwards

Structure - Approach -  Temperature falls, pressure falls, winds begin to gust, showers develop.
                  20-30km - Pressure decreases rapidly, 100km/h winds, cumulonimbus clouds give thunder and rain.
                  Eye - Period of calm, pressure very low temperature rises.
                  20-30km - Wind increases further, torrential rain, temperature drops further but pressure begins to rise.
                  Move away - Pressure and temperature rise, rain decreases, sunny intervals, winds drop.

Overall - It happens when warm air from the ocean rises and mixes with cool air above it. This produces storm clouds, rain, and strong swirling winds. When the winds hit 74 miles per hour, the storm is considered a hurricane. (2)

* Coriolis Effect - Results from the earth's rotation causing freely moving objects to veer towards the right in the Northern Hemisphere and to the left in the Southern Hemisphere.


(1) Access to geography - Hazards - Malcolm Skinner, 2003, p38-39
(2)  Scholastic News -- Edition 4; 9/10/2012, Vol. 75 Issue 2, p4-5, 2p

How are volcanoes monitored?

Below is a report by B.Slawinski, a year 10 pupil on his research into how volcanoes are monitored. It covers overall types with their individual details very well.

There are many different ways and techniques to monitor volcanoes, they are; seismicity, ground deformation, geophysical measurements, hydrology, gas and lastly remote sensing. In this fact file I will be showing when each of these techniques are used when they are used and how effective they are.

Seismicity

Seismic activity (earthquakes and tremors) always occurs as volcanoes awaken and prepare to erupt and are a very important link to eruptions. Some volcanoes normally have continuing low-level seismic activity, but an increase may signal a greater likelihood of an eruption. The types of earthquakes that occur and where they start and end are also key signs. Volcanic seismicity has three major forms: short-period earthquake, long-period earthquake, and harmonic tremor. Short-period earthquakes are like normal fault-generated earthquakes. They are caused by the fracturing of brittle rock as magma forces its way upward. These short-period earthquakes signify the growth of a magma body near the surface and are known as 'A' waves. Long-period earthquakes are believed to indicate increased gas pressure in a volcano's plumbing system. They are similar to the clanging sometimes heard in a house's plumbing system, which is known as "water hammer". These oscillations are the equivalent of acoustic vibrations in the chamber, in the context of magma chambers within the volcanic dome and are known as 'B' waves. Harmonic tremors are often the result of magma pushing against the overlying rock below the surface. They can sometimes be strong enough to be felt as humming or buzzing by people and animals, hence the name. Patterns of seismicity are complex and often difficult to interpret; however, increasing seismic activity is a good indicator of increasing eruption risk, especially if long-period events become dominant and episodes of harmonic tremor appear.

Gas emissions

As magma nears the surface and its pressure decreases and therefore gases escape. This process is much like what happens when you open a bottle of soda and carbon dioxide escapes. The main gases released are Sulphur dioxide and increasing amounts of it h erald the arrival of increasing amounts of magma near the surface. For example, on May 13, 1991, an increasing amount of sulphur dioxide was released from Mount Pinatubo in the Philippines. On May 28, just two weeks later, sulphur dioxide emissions had increased to 5,000 tonnes, ten times the earlier amount. Mount Pinatubo later erupted on June 12, 1991. On several occasions, such as before the Mount Pinatubo eruption and the 1993 Galeras, Colombia eruption, sulphur dioxide emissions have dropped to low levels prior to eruptions. Most scientists believe that this drop in gas levels is caused by the sealing of gas passages by hardened magma. Such an event leads to increased pressure in the volcano's plumbing system and an increased chance of an explosive eruption.

Ground deformation

Swelling of the volcano signals that magma has accumulated near the surface. Scientists monitoring an active volcano will often measure the tilt of the slope and track changes in the rate of swelling. An increased rate of swelling, especially if accompanied by an increase in sulphur dioxide emissions and harmonic tremors is a high probability sign of an impending event. The deformation of Mount St. Helens prior to the May 18, 1980 eruption was a classic example of deformation, as the north side of the volcano was bulging upwards as magma was building up underneath. Most cases of ground deformation are usually detectable only by sophisticated equipment used by scientists, but they can still predict future eruptions this way. The Hawaiian Volcanoes show significant ground deformation; there is inflation of the ground prior to an eruption and then an obvious deflation post-eruption. This is due to the shallow magma chamber of the Hawaiian Volcanoes;

Hydrology

There are 4 main methods that can be used to predict a volcanic eruption through the use of hydrology: Borehole and well hydrologic and hydraulic measurements are increasingly used to monitor changes in a volcanoes subsurface gas pressure and thermal regime. Increased gas pressure will make water levels rise and suddenly drop right before an eruption, and thermal focusing (increased local heat flow) can reduce or dry out aquifers. USGS scientists have developed an inexpensive, durable, portable and easily installed system to detect and continuously monitor the arrival and passage of debris flows and floods in river valleys that drain active volcanoes. Pre-eruption sediment may be picked up by a river channel surrounding the volcano that shows that the actual eruption may be imminent. Most sediment is transported from volcanically disturbed watersheds during periods of heavy rainfall. This can be an indication of morphological changes and increased hydrothermal activity in absence of instrumental monitoring techniques. Volcanic deposit that may be placed on a river bank can easily be eroded which will dramatically widen or deepen the river channel. Therefore, monitoring of the river channels width and depth can be used to assess the likelihood of a future volcanic eruption.

Remote Sensing

Remote sensing is the detection by a satellite’s sensors of electromagnetic energy that is absorbed, reflected, radiated or scattered from the surface of a volcano or from its erupted material in an eruption cloud. 'Gas sensing: Sulphur dioxide can also be measured by remote sensing at some of the same wavelengths as ozone. TOMS (Total Ozone Mapping Spectrometer) can measure the amount of sulphur dioxide gas released by volcanoes in eruptions Thermal sensing: The presence of new significant thermal signatures or 'hot spots' may indicate new heating of the ground before an eruption, represent an eruption in progress or the presence of a very recent volcanic deposit, including lava flows or pyroclastic flows. Deformation sensing: Satellite-borne spatial radar data can be used to detect long-term geometric changes in the volcanic edifice, such as uplift and depression.

Largest Earthquake Ever Recorded?

The question that I wanted to answer was "What was the largest earthquake ever recorded?". See below for the information I found out:

The largest earthquake ever recorded was in Valdivia in Chile. It occurred on the 22^nd May 1960 and was recorded at 9.5 on the Richter scale. It occurred in the afternoon at 15:11 local time. The earthquake also resulted in a tsunami which affected southern Chile, Hawaii, Japan, the Philippines, eastern New Zealand, southeast Australia and the Aleutian Islands in Alaska. The epiccenter was near Lumaco around 570km south of Santiago. The waves reached up to 25m in height. Two days after the earthquake, a volcanic vent close to Puyehue volcano erupted. This was caused by the Nazca Plate being subducted underneath the South American Plate on the Peru-Chile Trench.

Mt.Vesuvius eruption 79 AD

For my research today, I tried to answer the question of why Pompeii was so badly affected by the eruption of Mt.Vesuvius in 79 AD. Pyroclastic flows swept the city and everything was buried under an extremely hot layer of ash. The city was preserved in time and there was one thing which astounded archaeologists the most when they rediscovered the city. This was the human remains which were found on the site. Although the exact number of people who died in the eruption is unknown, it is predicted that a large proportion of the city's population was killed. There are a few reasons which could explain why the eruption had such a big impact on the city's population. Firstly, although the locals were aware of the plumes of smoke rising from the volcano (a journal was found documenting the signs leading up to the eruption) no precautions were taken. They thought of it as the gods letting off steam therefore no actions were taken until it was too late. Like volcanic eruptions in the modern world, tremors and seismic activities were felt leading up to the eruption. They also chose to ignore this as they were unaware of what could come next. When the volcano finally erupted, the people were caught by surprise and didn't know how to react. Some chose to flee the city and it is likely these people survived as the only affect on them was ash deposits. Those who chose to hide in the safety of their homes were the ones killed. As the pyroclastic flow swept the city, the infrastructure was unable to withstand the speed and temperatures and thus people were buried and burned. The main reason why the eruption of Mt.Vesuvius was so devastating was the lack of awareness. In the modern world, this could still be the case particularly in LEDCs. If large volcanoes are not monitored, locals could be at an increased risk as precautions and responses will not be taken to ensure they are safe. This shows that raising awareness and having an efficient system of response is vital in reducing the impacts of natural hazards, even in the modern world.

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My question was, how do explosions in volcanoes happen? What are the triggers?

 

The build up of hydrostatic pressure (pressure from magma at higher levels in the system) and the expansion of gas shoot lava high into the air. These lava fountains are commonly a few tens to hundreds of feet (meters) high. Less common are fountains that reach over 1,000 feet (300 m) in height. The highest 1959 lava fountain at Kilauea Iki reached 1,900 feet (580 m) in height. Thats 5 and a half football pitches.

 

Another example of an explosive type of eruption. Mount St. Helens in 1980 was an example. Such an eruption is driven by gas accumulating under great pressure. Driven by hot rising magma, it interacts with ground water until the pressure increases to the point at which it bursts violently through the over mantle of rock. In many cases, the rising magma will contain large quantities of partially dissolved gas. Sometimes a lava plug will block the conduit to the summit, and when this occurs, eruptions are more violent. With the sudden release of pressure following the initial explosion, the gas comes out of solution violently and explosively.

 

 

Wettonga tribe, Northern Australia

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Earthquake In England?

I was wondering why there are occasional EQ's in the UK even though we are not close to a plate boundary, where science tells us EQ's should occur.

In my research I found that the key to it all lies in the African and Eurasion plates movement. These have created multiple fault lines as shown in this image -


They occur more than we think - http://www.earthquakes.bgs.ac.uk/ - this shows the amount over the last 50 days with more detail within them.

Even the Daily Mail have got involved - http://www.dailymail.co.uk/sciencetech/article-1312608/UK-overdue-earthquake-kill-scores-people-moment.html - A slighlty exaggerated state of event but good detail nonetheless.

J.P.Strode

Are there volcanoes on other planets?

Are there volcanoes on other planets?                                                                  Olympus Mons - Mars

·         Dead volcanoes are found on Venus, Earth and its Moon, and Mars. Active volcanoes are located on Earth, Jupiter’s Io, and possibly on Venus, on Saturn’s Titan, and on Neptune’s Triton. Terrestrial and outer space volcanoes share some common properties.

·         Mars also has many distinctively volcanic features, including the largest volcano in the solar system, Olympus Mons, which towers 16 miles high over the Martian landscape. "If volcanism had occurred up until the last 1% of geologic time, it is very unlikely to have stopped," McEwen says. "We just haven't observed anything that is a smoking gun on either Mars or Venus.”

·         Volcanoes also shaped Mercury. There, however, the activity appears to have stopped operating early in the planet's history, billions of years ago. On our moon, too, volcanism operated early and then shut off sometime around 3 billion years ago.

Largest earthquake to happen with limited effect on human life?

 

Although these are very debatable because there can be no constant measurement of the earthquakes that go on under the entire ocean but the 1938 Banda Sea earthquake is up there. With a magnitude 8.5 on February 1 there was no deaths and the biggest problems were a pendulum clock stopping and glassware breaking on Banda and Kai islands. Bana Sea is near Indonesia to locate the example.

 

If you then want to contrast with some others then you can take Haiti, which was only magnitude 7.0 in June 2010 and killed 92,000. You could always take Kashmir 2005, killing 79,000, and was still only a 7.6. this means that it is almost 100 times bigger than Kashmir and still killed nobody.

 

Also follow @quakestoday for good infomation about the vast majority of earthquakes!

 

 

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