inquiry


 * 1 July 2008 - It is now 9 months since Ruapehu's last eruption,but Crater Lake temperatures and gas on Mt Ruapehu continue to be higher than normal, and are now referred to be GNS scietists as "signs of unrest".**

A [|lahar] at New Zealand's [|Mount Ruapehu] is all but over, without causing anywhere the level of havoc for which authorities were prepared. The event was first confirmed by a [|3 News] helicopter, and then the Department of Conservation. The Department of Conservation had said that a "moderate lahar" was moving down the side of Mount Ruapehu. The lahar travelled down the Whangaehu Valley, past the Tongariro catchment; and then continued on to the Tangiwai Bridge, the site of the 1953 [|Tangiwai disaster], which was itself caused by a lahar. The crater lake is currently being reported by a free phone number as at a warning level of 3a. The crater lake is also being reported at a level between 5.7-6.7 metres up the Crater Lake tephra dam. The lahar emergency plan was activated by Civil Defence. The district mayor of Ruapehu, Sue Morris, and conservation minister, Chris Carter, said that the authorities had been very quick to respond to the emergency. All three electronic surveillance technologies had their alarms activated. Mr Carter said, "The lahar travelled down the path as predicted, and the early warning response system that this government provided worked exactly as planned." Highways near Mount Ruapehu were closed by the [|Ohakune] police, including the [|Desert Road]. The roads have now been re-opened.
 * Sunday, March 18, 2007**

A lahar has been expected for a long time now, and scientists say the lahar could have been caused by, among other things, the bad weather New Zealand has been having lately. Since 1996 the water level in the crater lake at the top of Mount Ruapehu has been rising, which created a risk of a lahar last year. March 18, 2007. The long anticipated lahar finally happened! Steve and I were hired by TV3 News to get the first stabilised aerial shots of the lahar, as well as the aftermath. Features comments by local resident John Archer, who was present in 1953 when a similar lahar caused huge loss of life. Last time, the lahar destroyed a rail bridge, and in the dead of the night with no warning systems in place...a train drove straight off the edge and into the mudslide, most passengers perished. The 1953 incident is New Zealand's worst train disaster. Thankfully this time round nobody was hurt, people were prepared and the whole thing ran like clockwork. They have been waiting for this to happen for years, there were a whole bunch of seismic gadgets at the top of the mountain, as soon as the tremors were detected they sent their signals triggering road and rail closures for miles around...and everyone got out of the way!Was absolutely mind boggling to see and something I'll never forget. Most of the mountain shots were taken on sunrise the following morning, we had to get up the mountain early because of the weather closing in. The crater was covered in cloud and revealed itself for only a couple of minutes, just long enough to get the shots you see here. The views were just epic!The music is written and performed by a great friend, dylan lee.If you would like to see some awesome stills from the event, go to this page: http://www.geoffmackley.com/archive/ruapehulahar.htmlGeoff is a TV3 cameraman, he was first on the scene and got some great stills and video which I'm sure will be on his site soon. It was 1944 and the Second World War was raging. In Italy, American airmen were stationed at Pompeii Airfield when the debris started falling, but this was no ordinary wartime air raid. The cinder and rock dropping from the sky were being sent forth by the volcano dominating the horizon: Mount Vesuvius. Overhead, bombers wheeled in the air, their pilots’ minds turning from the threat of flack to an altogether more pervasive menace – but the damage the planes would be dealt was on the ground. It must have seemed like the earth's own call to arms in the face of the devastation taking place all around, and to the drafted witnesses it was difficult to describe. Some servicemen likened the mountain’s earthshaking eruption to bombs going off – ironic given the chronic danger of real shells exploding – while others evoked thunder to express the tremendous roaring noise made by the ground quaking. All comparisons to acts of both man and nature seemed to fail. The signs were there during the opening months of 1944. Small lava flows appeared at the rim of the great volcano, with small outflows of the molten rock. Still, the enlisted men would have little known what was coming, and the volcano fell quiet through the end of February and first half of March. Then, on March 18, following a battery of smaller explosions over several days, Vesuvius erupted. From Pompeii Airfield, just a few miles from the east-facing foot of Vesuvius, the men watched, awestruck, with no little apprehension clouding their thoughts. Amazing though the photos of the time are, one aspect of the eruption they cannot convey is the vivid orange hues of the molten rock that spat from the crater and advanced down the mountain, a seething river destroying everything in its path. A March 20 entry in a personal diary from the 489th Bomb Squadron Book reads: “To look above the mountain tonight, one would think that the world was on fire... As the clouds pass from across the top of the mountain, the flame and lava can be seen shooting high into the sky to spill over the sides and run in red streams down the slopes.” The entry continues: “Today it was estimated that a path of molten lava one mile long, a quarter mile wide, and eight feet deep is rolling down the mountain. Towns on the slopes are preparing to evacuate... The rumblings are now growing louder and the flame and sparks are flying higher. . . The mountain is really angry tonight. This is a sight to be remembered. An ironically beautiful sight.” As the ground continued to rumble over the ensuing days, Vesuvius belched dense, billowing smoke thousands of metres up into the air. The sustained ash plume, so brilliantly captured in the wartime photography of the time, was to prove one of the most destructive phases of the volcano’s bombardment, as all that Vesuvius had thrown up, came down – as if dropped from the clouds. In a diary entry from March 29 1944, the author in the 489th Bomb Squadron Book recalls the events leading up to the evacuation on March 22: “At 8 A.M. all hell broke loose. Black stones of all sizes, some as large as a football, fell in great quantity completely covering the ground, breaking branches from the trees, smashing through the tents to break up on their floors, tearing through metal, fabric and Plexi-glass of the aeroplanes. Soon all the tents were in tatters with much of their contents destroyed by direct hits.” It continues: “The storm of lava and rain continued through the morning piling up on the ground like snow and multiplying the damage. Soldiers who ventured from shelter wore steel helmets. Civilians covered their heads with pans, boxes or heavy baskets.” Perhaps surprisingly, no US Air Force men based at Pompeii were killed or seriously injured as a result of the eruption, though the volcano wiped out as many as 88 of the 340th Bombardment Group’s aircraft – more than any single Luftwaffe air raid. The hot ash, cinder and volcanic ‘bombs’ that blanketed the B-25 Mitchell bombers lying prone in the airfield caused irreparable damage such as burnt fabric control surfaces and cracked or melted windshields and gun turrets. All told, at least 26 people died and thousands were forced to flee their homes as the villages of San Sebastiano al Vesuvio, Massa di Somma and Ottaviano were obliterated; so too parts of San Giorgio a Cremano. Since then, Vesuvius has experienced its longest lull in activity in almost half a millennium. However, such a slumber will inevitably lead to a rude awakening – an eruption far more violent than 1944 – as the longer a volcano’s period of inactivity, the greater its magma build-up.

This begs the question: when might we expect to see the next show of force from Vesuvius? Scientists can but speculate – while continuing to closely monitor the lava cone for any sign of change – though an emergency evacuation plan is in place for the surrounding towns and villages. vesuvius,crater,died,lava,1944,ash,eruption,violent,angry & obliterated!

WEEK 6

Q 1. How do ponds and lakes form?

There are a number of natural processes that can form lakes. A recent tectonic uplift of a mountain range can create bowl-shaped depressions that accumulate water and form lakes. The advance and retreat of glaciers can scrape depressions in the surface where water accumulates; such lakes are common in Scandinavia, Patagonia, Siberia, and Canada. The most notables examples are probably the Great Lakes of North America.

Lakes can also form by means of landslides or by glacial blockages. An example of the latter occurred during the last ice age in the U.S. state of Washington, when a huge lake formed behind a glacial flow; when the ice retreated, the result was an immense flood that created the Dry Falls at Sun Lakes, Washington. Salt crystals, on the shore of Lake Urmia, Iran Salt crystals, on the shore of Lake Urmia, Iran

Salt lakes (also called saline lakes) can form where there is no natural outlet or where the water evaporates rapidly and the drainage surface of the water table has a higher-than-normal salt content. Examples of salt lakes include Great Salt Lake, the Caspian Sea, the Aral Sea, and the Dead Sea.

Small, crescent-shaped lakes called oxbow lakes can form in river valleys as a result of meandering. The slow-moving river forms a sinuous shape as the outer side of bends are eroded away more rapidly than the inner side. Eventually a horseshoe bend is formed and the river cuts through the narrow neck. This new passage then forms the main passage for the river and the ends of the bend become silted up, thus forming a bow-shaped lake.

Crater lakes are formed in volcanic calderas which fill up with precipitation more rapidly than they empty via evaporation. An example is Crater Lake in Oregon, are located within the calderas of Mount Mazama. The caldera was created in a massive volcanic eruption that led to the subsidence of Mount Mazama around 4860 BC. the largest lake in the world is named a "sea"

Some lakes, such as Lake Jackson in Florida, USA, come into existence as a result of sinkhole activity.

Lake Vostok is a subglacial lake in Antarctica, possibly the largest in the world. The pressure from the ice atop it and its internal chemical composition mean that if the lake were drilled into a fissure could result that would spray somewhat like a geyser.

Most lakes are geologically young and shrinking since the natural results of erosion will tend to wear away the sides and fill the basin. Exceptions are those such as Lake Baikal and Lake Tanganyika that lie along continental rift zones and are created by the crust's subsidence as two plates are pulled apart. These lakes are the oldest and deepest in the world. Lake Baikal, which is 25-30 million years old, is deepening at a faster rate than it is being filled by erosion and may be destined over millions of years to become attached to the global ocean. The Red Sea, for example, is thought to have originated as a rift valley lake.

Q 2. Name at least one organism found in each of the pond habitats?

on the shore - grasses in the shallow water near shore - tadpoles at the bottom of the pond - algae at the surface of the pond - mosquitos

Q 3. How can building up natural leaves with stone and concrete often make flooding worse downstream

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