Goldstein - 101 Amazing Facts about Volcanoes

Title Page

101 AMAZING FACTS ABOUT VOLCANOES

Jack Goldstein

Publisher Information

Published in 2014 by

Andrews UK Limited

www.andrewsuk.com

The right of Jack Goldstein to be identified as the author of this work has been asserted by him in accordance with the Copyright, Designs and Patents Act 1998

Copyright 2014 Jack Goldstein

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means without the prior written permission of the publisher, nor be otherwise circulated in any form of binding or cover other than that in which it is published and without a similar condition being imposed on the subsequent purchaser. Any person who does so may be liable to criminal prosecution and civil claims for damages.

All information contained within this book has been researched from reputable sources. If any information is found to be false, please contact the publishers, who will be happy to make corrections for future editions.

Introduction

Did you know that animals can often sense when a volcano is going to erupt? Or that the force of an eruption is measured on the VEI, or Volcanic Explosivity Index? What is the difference between a shield volcano and a stratovolcano? And what were the largest eruptions in human history? All of these facts and more can be found in this fantastic guide to volcanoes, separated into sections for easy reading. This book is perfect for those studying volcanoes at school, or even if you are just interested in finding out more about this fascinating topic.

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The Basics

1. Volcanoes are ruptures in the surface of the earth (or other planets) that allow lava, volcanic ash and gas to escape.
2. A volcanic eruption is caused when gas pressure builds up inside the volcano, eventually expelling out hot magma under enormous pressure.
3. Many people think volcanoes are fiery mountains, and although some fall into that category, there are many other types.
4. Some volcanoes feature wide plateaus, other are bulging domes, and some are fissure vents - wide cracks from which lava emerges.
5. Although it is normal to think of volcanoes as being on land, there are in fact many found on the ocean floor, and some even under the planets icecaps!
6. An active volcano is one that displays regular activity, from escape of gases or small lava flows to a full eruption.
7. A dormant volcano is one that we know has had some historical activity, but is currently quiet.
8. An extinct volcano is one that is never recorded in human history as having displayed activity and is not believed to ever erupt again.
9. People who study volcanoes are called volcanologists.
10. Volcanologists try to predict a volcanos future activity by analysing a number of factors, a key one being the use of specialist equipment to actually listen to the sounds being made inside it.

Terminology

1. Magma - this is the hot liquid rock under the surface of the earth.
2. Lava - after magma erupts from a volcano, it becomes known as lava.
3. Ash - ash is defined as fragments of volcanic rock that are smaller than 2mm in size.
4. Pumice - when lava cools it can become this highly porous rock. Its bubbly nature is formed by water that is dissolved in the Lava which is rapidly cooled after eruption.
5. Tectonic Plates - huge plates of rock often thousands of miles across that sit on the earths surface and move a few centimetres every year. Where these meet, there is often activity such as earthquakes and volcanoes.
6. Vent - the opening in the earth from which the volcanic material escapes.
7. Crater - this is the mouth of the volcano, the part that surrounds the vent.
8. Flank - this is the scientific name for the side of a volcano.
9. Summit - this is the highest point of the volcano.
10. Sill - this is a flat piece of rock which is formed when magma inside a volcano finds its way into a crack and then hardens.

The Largest Eruptions

In Human History

1. Huaynaputina, a volcano in Peru, erupted in 1600AD. The explosion was so powerful that it caused mudflows over seventy miles away. The ash cloud altered the worlds climate to such an extent that the next few summers were the coldest in a five hundred year period.
2. In 1883, the eruption of Krakatoa was heard thousands of miles away. The force of the explosion destroyed the entire island on which the volcano was based, and it created a tsunami forty metres tall which killed more than thirty thousand people.
3. After sitting silently for five hundred years, Santa Maria in Guatemala decided to erupt in 1902. So great was the force of the explosion that a crater almost a mile wide was formed on the volcanos flank.
4. When Novarupta in Alaska erupted in 1912, an astonishing three cubic miles of magma were ejected under enormous pressure. An area some three thousand square miles in size was covered in 25cm of ash.
5. The strongest explosion ever witnessed by humans is believed to be that of Mt. Thera on the Island of Santorini in Greece. After studying the area, which was previously inhabited by the Minoan civilization, geologists say that in 1610 BC the volcano exploded with the energy of more than two hundred atomic bombs.
6. Mount Pinatubos eruption in 1991 sent a cubic mile of magma an incredible twenty-two miles into the air. So much ash settled on homes across the Philippines that many roofs caved in under the weight.
7. The caldera formed by the eruption of Ambrym Island in 50AD is an incredible eight miles wide. The volcano, located in the Republic of Vanuatu in the south-western Pacific remains one of the most active in the world today.
8. The Ilopango Volcano in El Salvador erupted so violently in 450 AD that most of the entire country was covered in volcanic material. Thousands of inhabitants of the early Mayan cities had to flee their homes, the their entire civilization changed from being one based in the highlands of EL Salvador to the lowlands of Guatemala and the north of the country.
9. On the border between China and North Korea lies Changbaishan, a volcano which erupted around one thousand years ago. So much pressure had built up that volcanic material was blown around seven hundred miles away to northern Japan.
10. In 1815, Mt. Tambora on Indonesias Sumbawa Island erupted with devastating effects. Killing over seventy thousand people, the force 7 explosion (known as super-colossal) was heard over 1200 miles away.

General Facts

1. There are thought to be around 1500 active volcanoes in the world, based on the number that are known to have erupted in the last ten thousand years.
2. However, some volcanologists point out that there could be thousands more on the sea bed of which we are unaware.
3. There are three different kinds of volcano. The first are known as shield volcanoes . These have lava flows with low viscosity (meaning they are thin and not very sticky) which flow for many miles. These volcanoes are therefore very wide and have smooth, shallow slopes.
4. The second type, stratovolcanoes , are usually the largest. They can have many different types of eruption containing ash and rock, which means that grow to astounding heights.
5. The third type are cinder cone volcanoes . These are usually much smaller - only around 400m high - as their eruptions are very short-lived.
6. The force of a volcanic eruption is measured on the VEI, or Volcano Explosivity Index . The scale goes up to 8.
7. Indonesia is the country believed to be home to the highest number of active volcanoes - 76 at the last count.
8. Although most volcanoes are formed at the edge of tectonic plates, others lie on single hotspots and tend to have magma which bubbles up from much deeper in the earth which builds up to phenomenal pressure. These are known as supervolcanoes .