The Volcanoes - Los Volcanes

Bueno aquí os dejo un vídeo de un documental de Discovery Channel que habla sobre los volcanes, espero que os guste:

POMPEII: THE LAST DAY

"You could hear women lamenting, children crying, men shouting. There were some so afraid of death that they prayed for death. Many raised their hands to the gods, and even more believed that there were no gods any longer and that this was one unending night for the world."
—Pliny the Younger, circa A.D. 97 to 109

WHAT HAPPENED HERE

August 25, A.D. 79

It all lasted 19 hours.

Then, there was only a long, deathly silence. Pompeii lay buried for nearly 1,700 years. It wasn't until 1748 that archaeologists began slowly uncovering the ancient city, preserved under 9 feet of volcanic ash and frozen in time by Pliny the Younger's vivid report.

About three-fifths of the city has been liberated from the solidified volcanic ash and pumice that engulfed it. But many questions remained unanswered for a long time.

What was life like under the volcano? What exactly did happen that summer day in A.D. 79? Here we take a look into the latest findings.

WHY IS VESUVIUS LOCATED WHERE IT IS? GLOBAL PERSPECTIVE

Vesuvius is near a place where one section of the Earth's surface is being pushed down below another section. These sections are called plates. When plates grind against one another two things can result--earthquakes and volcanoes. Volcanoes begin to form when the rocks of the lower plate get pushed deep into the Earth. There they are heated, until they melt, forming magma, one kind of liquid rock. Because magma is less dense than the solid rock around it, it is pushed upward. If this magma finds a weak place at the Earth's surface, it may break through and form a volcano.

Subduction

WHAT KIND OF VOLCANO IS VESUVIUS? VOLCANO TYPES

Vesuvius is a stratovolcano (or composite volcano), made up of alternate layers of ash and lava. Stratovolcanoes normally have two different kinds of eruptions. One kind produces mostly ash and cinders. The other kind produces lava. In Vesuvius these two types of eruption have not been seen to happen together.


INSIDE A VOLCANO

This is a type of volcano called a stratovolcano. You can see how this very tall volcano has been built up by layers of ash and lava from previous eruptions. The volcano is currently dormant. But it is about to re-awaken!

Because it is lighter than solid rock, magma (molten rock) has been rising to form a huge pool, called a magma chamber, beneath the volcano. The volcano will erupt when gases held within the magma burst out explosively, now that they are under less pressure than when the magma was deeper within the earth.

The explosive escape of the gases from the magma causes a violent eruption which literally "blows the top" off the volcano. Gas, blobs of magma (now called lava), chunks of rock, and fine debris called volcanic ash are blasted upwards. (The ash, because it is very light, may reach heights sufficient to endanger jet airplanes.)

Because the fragments of rock and ash (pyroclastics) are heavier than air and may not mix with enough air to remain high aloft, they may surge down the sides of the volcano as dangerous "pyroclastic flows."

Within the flow, heavier particles sink and the lighter particles and gases are displaced upwards. The flow meanwhile surges along like a boiling cloud. Pyroclastic flows can travel at speeds greater than 100 miles per hour and can be as hot as the inside of a kiln. Such flows killed 29,000 people in the 1902 eruption of Mount Pelée, Martinique.

WOULD YOU SURVIVE?

The volcanic eruption of Mount Vesuvius in A.D. 79 caught most of the Roman population off guard. Would you have made it?

Estructura y dinámica terrestre

Sin duda esta animación que vimos el último día de clase os ayudará a entender mejor la estructura y el funcionamiento de nuestro amado planeta Tierra (el único que por ahora habitamos).

Fuente: El País.

Un tsunami imprevisto

Bueno aquí os dejo un vídeo de un tsunami; mientras que un surfista estaba surfeando, le vienen olas gigantescas que se acercan a él, y al final del vídeo, se le pierde de vista y probablemente, muere. Espero que os guste:

Tsunami en el Océano Índico

Os pongo este video que encontré por el Youtube en el momento en el que el Tsunami entra en tierra:

Comportamiento de Volcanes y Tipos

Ya que el último vídeo de Volcanes que subí al Blog no fue bastante bueno, he encontrado otro más interesante y novedoso: Es un Documental que habla sobre los Tipos de Volcanes y su Comportamiento, de Discovery Channel. Espero que os guste:

Documental sobre la Falla de San Andrés

Bueno aquí os dejo otro vídeo que encontré en YouTube en el que habla de las Placas Tectónicas, especialmente hace incapié en la única placa téctonica del mundo visible y que se puede tocar propiamente, la conocida Placa de la Falla de San Andrés, en California. Espero que os guste este documental y que sepáis más sobre las placas tectónicas:

The volcanic eruptions

Bueno aquí os dejo un nuevo vídeo que encontré por YouTube en el que se habla de las erupciones volcánicas, diciendo que son nocivas para el medio ambiente, debido a que destruyen la Capa de Ozono. Espero que os guste y os déis cuenta de lo grave que es este tema:

Plate tectonics theory

Os dejo estas animaciones sobre la teoría de la Tectónica de Placas. Están en inglés, para que os vayáis acostumbrando, y los conceptos pueden resultar complicados de entender para vuestro nivel. Sin embargo fijaros que muchas de las animaciones se parecen a las ilustraciones de vuestro libro de texto y por tanto no será dificil sacar conclusiones de ellas.