I pulled the information from another site. I wish I could see something in the web cam; however, currently darkness. If Katla does blow you will have a front row seat Ríkisútvarpið vefur Very scary! UPDATED INFORMATION - Get professional opinions from actual scientists at this link, read the comments. [link to www.scienceblogs.com] Harmonic Tremors - Usually in the 1-5 Hz range [link to www.springerlink.com] Harmonic tremor is widely studied and modelled in a very narrow frequency band (1–5 Hz) which represents the eigenfrequencies of a resonator assumed as the source of the phenomenon. Katla Harmonic Tremor Chart - Recorded in the 1-4 Hz range. [link to www.hraun.vedur.is] Katla Web Cam - Regardless if pointed at Katla or Ejall... Katla activity can be seen here once eruption begins. Unless the cam is destroyed. [link to www.ruv.is] Eruption Types - There are 5 types of volcanic eruptions on land and one type for under sea eruptions. The names are based on the general observations at a specific location or event. They are listed in order of least energetic to most energetic. (1) Hawaiian type - Characterized by lava-effusion. Frequently begins with a lava fountain. Low silica type magma with high viscosity. Often streams long distances from volcano. (2) Strombolian type - Viscous magma with gases that escape intermittently when rising to the surface. Often results in blocks and bombs which fall on the surrounding landscape. Lava flows are common. (3) Vulcanian type - Burst into life suddenly after dormant periods. Begins with a violent, loud explosion. Gives off more gases as well as ash, cinders and pumice. Typically Vulcanian Volcanoes have long dormant periods with moderate eruption lengths. (4) Pelean type - Develope on Strato-Volcanoes and magma has high concentration of silica. Typically vents ash weeks before explosive eruptions. A dome top is often formed and is blown away upon eruption. Long dormant periods of decades and longer. (5) Plinian type - The most aggressive of all volcanic eruptions. Eruptions occur when highly viscous magma and gases explodes at greater depths in the crater pipe that mimics a shotgun barrel in effect. Large amounts of gas is erupted at very high speeds resulting in an enormous ash cloud. Plinian eruptions can blast ash very high into the atmosphere which often results in climate changes. The caldera often collapses after eruption ends. (*) Submarine type - Can be any of the 5 but under water. Katla is a Plinian type A well known Plinian eruption is Vesuvius in 79AD. This is the best example to describe Katlas current state. Add the 750+km3 of galcial ice and a very potent mix is created. When will Katla Erupt? - Nobody knows for sure but historical records are very suggestive. Locals to the Icelandic volcano suggest April 25th as the date of eruption. Who knows better then the locals? Plus the harmonic tremors of Katla are showing signs of an eruption any day now. What is happening is the harmonic tremors are gradually weakening which is showing a gaining of pressures in the magma chamber(s). This will not result in a dormant state. It will result in an eruption to release the pressures. At first, the eruption magma and gases will hit the glacial ice with extreme amounts of energy. The ice will flash to steam very quickly increasing pressures to an unbelievable pressure. Eventuall the ice on top will not hold the pressures and results in a massive version of a dry ice bomb. Anyone who has made dry ice bombs know how freaking loud they are. This eruption is going to be a massive explosion in the order many many times greater then St Helens. Very fine ash will circle the globe causing troubles in many areas. Commercial airliners will go bankrupt. Military will reduce training in air. Global temps will drop. Crops will partially fail in certain areas near geoligical borders. i.e. - crops on the edge of climate zones. The worst winter ever seen in our lives will occur. The summer will fail to happen. And on a good note, the world will have the most beautiful sunsets ever seen in our lifetimes. Firery reds, oranges, yellows and even greens in the sunsets. Pay attention on April 25th 2010. That is the anticipated day of eruption. The MSM was ordered not to broadcast this prediction on the knowledge it would severly disrupt commercial airtravels. The industry is already suffering and any more fears would likely send some airline industries into bankrupcy. This is being avoided at all costs. Engine damages from Ejall are being swept under the carpet. Most of us see this happening.