Geysers & Volcanoes (Spain)A quick but precise walkthrough.

José Jiménez Luna 2ºBach A

Tips before the start

1. Click any word you don’t know the meaning of and you will be directed into a Thesaurus dictionary reference.

2. There will also be links to many YouTube optional videos. If an internet connection is not available at that moment, I will include those videos in a portable storage disk.

3. To make things easier to those not very familiarized with science, explanations shall not be very hazardous to understand.

4. Copy & Paste is not used, you can simply check this by using Google. Sources are shown at the end.

5. Effects will only be used only in those slides I consider to be appropiate. If you want to disable background music, turn your headphones/speakers off.

6. Learn & Enjoy.

Behavior of a volcano

A volcano can be defined as any crater or opening in the Earth's surface which allows molten rock and volcanic gases to escape from the inner layers of the Earth.

Volcanoes are usually mountainous in shape, but they can appear in nearly any form, like volcanic vents existing on the ocean floor, ice volcanoes, (Jupiter, Saturn and its moons), and volcanoes that are simply a crater in the ground.

I will show an example of each one. Simple crater

Some examples

Volcanic Vent Ice Volcano

Main volcano types Every volcano has a different eruptive

history. However, we are able to clasify them in three main types.

TYPE SHAPE COMPOSITION ERUPTION

Scoria Cone Basalt tephra, occasionally andesitic

Strombolian

Shield Volc. Basalt lava flows

Hawaiian

Stratovolcano Variable Plinian

Lava composition

Generally, most lava is of basaltic composition. Basaltic melts have usually lower gas contents and are very fluid.

Its lower density is due to their lower SiO2 (silica) contents. When gases are thrown/expelled from basaltic melts they are allowed to rise unimpeded through the fluid magma without a significant build up of gas pressure. This results in relatively calm, nonexplosive eruptions, and a preponderance of lava.

How Volcanoes Work - Optional Video

Lava composition (2)

A) Pahoehoe Lava: typically the first to erupt from a vent. They are relatively thin (1-2 m) and very fluid. No viscosities. Pahoehoe is often converted to a'a lava as it advances downslope, away from the volcano.

There also lavas with unusual composition, like andresite, dacite ot carbonatites although these are less common

B) A’a Lava: these lava flows are often more viscous, and typically thicker, than pahoehoe lavas they tend to advance at greater rates. Their flow fronts can vary from two meters to as much as twenty meters thick

Basaltic lava can be classified into two subtypes:

Eruption Types

Although eruption types depend greatly on the magma composition, we are able to clasify them.

a) Fissure erup: fissure eruptions are generated at several contemporaneous sites along a linear fracture, or along an echelon.

b) Hawaiian erup: calmest of the eruption types. They are characterized by the effusive emission of highly fluid basalt lavas with low gas contents

Eruption types (2)

c) Strombolian erup: short-lived, explosive outbursts of pasty lava ejected a few tens or hundreds of meters into the air.

d) Vulcanian erup: most often associated with andesitic to dacitic magma. The high viscosity of these magmas makes it difficult for the vesiculating gases to escape

e) Plinian erup: associated with volatile-rich dacitic to rhyolitic lava, which typically erupts from stratovolcanoes.

f) Hydrovolcanic eruptions :generated by the intereaction of magma with groundwater.

Geysers

A geyser is a vent in Earth's surface that periodically ejects a column of hot water and steam (gas). Even a small geyser is an amazing phenomenon; however some geysers have eruptions that blast thousands of gallons of boiling hot water up to a few hundred feet in the air.

There are certains conditions required to form a geyser:

A) Hot rocks below (or even lava) B) Subterranean water source C) A wide fissure. D) An ample ground water source

There are no active famous geysers in Spain. However there is an artificial one in Timanfaya Park (Lanzarote). Here is a video demonstration.

Spanish Eruptions

There are several zones with volcanic activity in Spain. These are not always in the peninsula itself, but in the Canary Islands.

However, we can find some in the peninsula, like La Garrotxa (Gerona), Cabo de Gata (Almería), Cofrentes (Valencia), y Campos de Calatrava (Ciudad Real).

Landscape changes due to Chinyero vulcano eruption in Tenerife (1909) - Optional Video

Calatrava Volcanoes – Optional Video

Last eruption (1971) Was the shortest eruption ever recorded in the

history of the Canary Islands, considering the one that happened in the XVIII century, which lasted about 6 years

There have always been eruptions (16 recorded) in the Canary Islands zone, none with mortal victims. This was only possible due to the low demographic density and the fluency of the lava emitted by the volcanoes.

The volcano caused material damages, it destroyed vine cultivation zones and destroyed a beach, although another was formed thanks to the corrosive power of the lava.

It didn’t affect high density zones thanks to the proximity of the beach. The lava poured to the sea was solified, making the island grow in size.

Speculation

According to Ramón Ortiz, vulcanologist and researcher from the CSIC: “An eruption can occur unexpectedly at any time in any volcanic zone of the peninsula itself or the Canary Islands. In Latin America or Africa, an annual eruption is common, but not in Europe; that is why people tend to think there is no vulcanic activity in Europe. However, there have been 4 eruptions in Tenerife in the last 100 years.”

Recent investigations have shown that the eruption of certain volcanoes in Europe might have caused the dissappearance of the Homo Nehanderthalis. Nevertheless it didn’t extinguish those inhabiting Africa and Asia zones.

Speculation (2)

Regarding geological issues, the Canary archipelago would have been about 10 times bigger 60 million years ago than it is nowadays. According to Fernández Palacios, Geology professor and reasearcher from Masachussets MIT, there could be many other islands hidden hundreds of meters under the sea.

The islands we know today are only a fraction of what they used to be. Fuerteventura emerged 20 million years ago, Gran Canaria 15mill, Tenerife 11mil ago, and Fuerteventura 1mill ago.

Several technological improvements have achieved to chart the sea bottoms under the archipelago and the island of Madeira

Many mountains and hills were discovered under sea thanks to these techniques

Optional Content

Sources

http://sobrecanarias.com/2008/06/02/timanfaya-parque-nacional-en-lanzarote/ http://sobrecanarias.com/2010/04/07/geiser-en-el-parque-nacional-de-timanfaya/ http://geology.com/articles/geyser.shtml http://www.eldigitaldecanarias.net/noticia22614.php http://corunaenredada.blogspot.com/2008/07/la-ultima-erupcion-de-un-volcan-en.html http://www.fomento.es/MFOM/LANG_CASTELLANO/DIRECCIONES_GENERALES/INSTITUTO_GEOGRAFICO/Geofisica/volcanologia/C20_ERUPCIONES_HISTORICAS.htm http://www.geology.sdsu.edu/how_volcanoes_work/Home.html