A Kos volcano tour is a trip from the island of Kos to a volcano of the Dodecanese. It is one of the Greece tours that set the sea, the islands and the volcanic rock of the Aegean side by side.
What does a Kos volcano tour mean?
A Kos volcano tour is a trip centred on volcanoes. A volcano is an opening or crack in a planet’s crust that lets lava, ash and gases escape. Lava is molten rock that has reached the surface, while magma is the same rock still underground.
Anyone curious about a Kos volcano tour can start with how a volcano works. A volcano needs three parts. Magma supplies the molten rock. A conduit, which is a channel, carries that rock upward. A vent, the opening at the surface, lets it out. Together, these three parts make a working volcano.
Erupted lava and tephra pile up around the vent. Tephra means the loose rock and ash thrown out by an eruption. This material forms a volcanic edifice, which is a cone or a mountain. A Kos volcano tour is easier to follow when these terms are clear.
Plates are huge slabs of the planet’s crust. In subduction, a plate under the ocean dives beneath a plate carrying a continent. This forms a deep ocean trench. A mid-ocean ridge is a mountain chain on the sea floor. Where such a ridge rises above sea level, volcanic islands form, such as Iceland.
Shield volcanoes are named for their broad, shield-like profiles. Lava domes have steep sides built by slow eruptions of thick, sticky lava. Cinder cones form from loose rocky pieces that build up around the vent. These shape names also help when reading about any Kos volcano tour.
- Fissure vents: These flat, straight cracks let basaltic lava, a lava type named for basalt rock, emerge.
- Hotspots: These volcanic areas are thought to be formed by mantle plumes, which are columns of hot material.
- Supervolcanoes: A supervolcano produced over 1,000 cubic kilometres of deposits in a single explosive event.
Submarine volcanoes sit on the sea floor. Volcanic activity in the Holocene, the current geological epoch, has been documented at only 119 of them. A Kos volcano tour is one small part of a very large subject.
On a Kos volcano tour, what does magma add?
A Kos volcano tour makes more sense once one key word is explained in plain English first. Magma is the molten or semi-molten material that forms igneous rock. Igneous means the rock began as melted material that later cooled and set hard.
Magma forms when either the mantle or the crust melts. The crust is the thin outer shell of Earth. The word mantle names the thick layer of rock beneath the crust. Melting takes place in settings including subduction zones, where one plate of the crust sinks slowly beneath another.
Rising magma ends in one of two ways. It can erupt as lava, which is magma that has reached the surface. It can also solidify underground as an intrusion, a body of magma that hardens below the surface. Knowing both outcomes makes any Kos volcano tour easier to follow.
Underground magma bodies take forms such as dikes, sills, plutons and batholiths. A dike is a thin sheet that cuts across rock layers. A sill is a thin sheet that runs between layers. Plutons and batholiths are far larger masses. A reader planning a Kos volcano tour can learn these names first.
Temperatures differ from one kind of magma to the next. Typical molten lava sits between 700 and 1,400 °C. Mafic magma, also called basaltic magma, tends to erupt at 1,100 to 1,200 °C. Komatiite magma is thought to have erupted at 1,600 °C, above that lava range.
- Felsic magma: It contains more than 63% silica, a hard mineral compound found in rock.
- Andesitic magma: It contains 52% to 63% silica, so it holds less silica than felsic magma.
- Dissolved water: It sharply reduces the viscosity, or thickness, of molten rock, so the rock flows more easily.
Once crystals reach about 60% of the magma, it stops behaving like a fluid. A typical magma is a Bingham fluid, which resists flow until a yield stress, or push, is crossed. Both facts round out the science behind a Kos volcano tour.
On a Kos volcano tour, what does lava add?
A Kos volcano tour is a fitting place to ask what lava is. Magma is molten rock that sits in the interior of a planet or moon. Lava is that same magma once it has been pushed out onto the surface.
Lava can erupt onto land or onto the sea floor, or be thrown into the air. A lava flow is lava that pours out during an effusive eruption. An effusive eruption is one that pours lava out. These are the basic terms behind any Kos volcano tour topic.
Lava can flow great distances before cooling makes it solidify, which means turn from liquid into solid. Lava exposed to air quickly forms a solid crust on top. That crust insulates the liquid lava beneath it, so the liquid below cools more slowly. This background helps a reader make sense of a Kos volcano tour.
Volcano science uses two special names for basaltic lava, which is lava made of basalt rock. Pāhoehoe is basaltic lava with a smooth, billowy, or ropy surface. ʻAʻā is basaltic lava with a rough surface of broken blocks called clinker. Knowing both names sharpens how a reader thinks about a Kos volcano tour.
Lava tubes can carry molten rock kilometres from the vent with little cooling. A vent is an opening where lava leaves the ground. A lava fountain forcefully but non-explosively ejects lava from a crater, vent, or fissure. A crater is a hollow at a volcano’s opening, and a fissure is a long crack.
- Lava lakes: Permanent lava lakes exist at only a handful of sites in the world.
- Lava deltas: Lava deltas form where lava flows on land enter standing water.
- Entablature: The irregular upper part of a solidified lava flow is called the entablature.
Molten lava types range from about 800 to 1,200 °C, depending on chemical composition. Chemical composition means the mix of substances in the rock. The word lava names a family of materials. That variety is what a Kos volcano tour can teach about it.
On a Kos volcano tour, what does tephra add?
A Kos volcano tour brings up one useful science word: tephra. Tephra is fragmental material from a volcanic eruption, whatever its composition or fragment size. Fragmental means made of broken pieces, and composition means what the pieces are made of.
The Greek word téphra means ash. Volcanologists, the scientists who study volcanoes, also call airborne fragments pyroclasts. Airborne means thrown into the air by an eruption. Pyroclast comes from Greek words meaning fire and broken in pieces. Learning these names is a simple first step before a Kos volcano tour.
Size sets the name of each kind. Ash is tephra with particles smaller than 2 mm in diameter. Lapilli, also called volcanic cinders, measure between 2 and 64 mm. Volcanic bombs and volcanic blocks are larger than 64 mm in diameter. Anyone preparing for a Kos volcano tour can learn these size names.
Tephra includes glassy particles that form as droplets of magma cool. A droplet is a tiny blob of liquid. Magma is melted rock that sits below the ground. Glassy means the particles are made of glass. Glass in tephra is a short, simple topic to learn ahead of a Kos volcano tour.
A clast is a single broken piece of rock. Fallen clasts stay tephra unless strong heat fuses them into pyroclastic rock or tuff. To fuse is to join into one solid mass. Pyroclastic means made of pyroclasts, the airborne fragments named earlier. Tuff is the name for the rock that results.
- Tephrochronology: This method treats separate layers of ash from one eruption as a time framework.
- Marker horizons: Tephra layers carry their own chemistry and act as markers in archaeological and geological sites.
- Cryptotephra: This very small tephra measures 25 to 125 micrometres and is invisible to the naked eye.
Ash can remain in the stratosphere for days to weeks after an eruption. The stratosphere is the high layer of air above the clouds. With these terms known, any Kos volcano tour that mentions tephra is simpler to follow.
On a Kos volcano tour, what does volcanic gas add?
A Kos volcano tour adds a lesson in volcanic gas. Active volcanoes give it off, and dormant ones, which rest between eruptions, release it at times. The main parts of the gas and the way it escapes are easy to explain.
Emissions are the gases a volcano gives off. A Kos volcano tour can start with their basic mix. Water vapour is water in gas form. It leads them and normally makes up more than 60% of the total. Carbon dioxide makes up 10 to 40% of volcanic emissions in the normal case.
High-temperature gases carry sulfur as sulfur dioxide, and low-temperature gases carry it as hydrogen sulfide. From 2005 to 2015, eruptions averaged 2.6 teragrams of sulfur dioxide a year. A teragram is a unit of mass for huge amounts. Passive degassing, gas released without an eruption, gave 23.2.
Substances that can become gaseous when heated are called volatile substances. The word magma means molten rock that lies under the surface. Viscosity means how thick and sticky magma is. Its total volatile content and its viscosity decide whether gas escapes gently or violently. Readers planning a Kos volcano tour can learn these terms first.
In open system degassing, gas separates from its magma and rises without staying in equilibrium with it. In closed system degassing, gas and its parent magma rise together while staying in equilibrium. Equilibrium is a steady balance; degassing is gas leaving magma. Both terms are easy to learn before a Kos volcano tour.
- Molten rock: Molten rock near the atmosphere releases high-temperature volcanic gas above 400 °C.
- Eruptive share: Eruptive carbon dioxide accounts for less than 10% of total annual volcanic carbon dioxide output.
- Ultraviolet light: Sulfur dioxide absorbs ultraviolet light strongly, and its background level in air is low.
A Kos volcano tour sits within a long line of gas study. Scipione Breislak collected and analyzed volcanic gases in Italy as early as 1790. That work shows that the study of volcanic gas has a long record.
On a Kos volcano tour, what does a phreatic eruption add?
A Kos volcano tour makes more sense with one word in hand: phreatic, meaning a steam-driven blast. A phreatic eruption occurs when magma, the hot melted rock underground, heats ground water or surface water. An eruption is a burst of material out of the ground.
Ground water is water held in soil and rock below the surface. Surface water is water lying on top of the ground. Magma heat causes either kind to turn into steam almost instantly. Anyone planning a Kos volcano tour can use that simple picture as a base for later terms.
The explosion throws out steam, water, ash, rock and volcanic bombs. Ash is made of tiny bits of rock. A volcanic bomb is a lump of rock thrown through the air. Fragments thrown out by the blast range from cold to incandescent, which means glowing with heat.
Hundreds of steam explosions came before the 1980 eruption at Mount St. Helens. At the 2021 La Palma eruption, new vents tended to announce themselves with a phreatic explosion. A vent is an opening in the ground where an eruption breaks out. Both cases are useful background for a Kos volcano tour.
Kilauea in Hawaii has a long record of phreatic explosions. A phreatic eruption in 1924 hurled rocks estimated at eight tons. A ton is a unit of weight, and eight tons is a heavy load to throw. Cases like these widen the background for a Kos volcano tour.
- Other names: Phreatic eruptions are also called phreatic explosions, ultravulcanian eruptions or steam-blast eruptions.
- Phreatomagmatic: Volcanologists, the scientists who study volcanoes, call an eruption phreatomagmatic if molten magma is included.
- Maars: Phreatic eruptions can create maars, which are broad, low craters, or wide hollows in the ground.
Magma temperature can range from 500 to 1,170 °C. That figure shows the scale of the heat behind a phreatic eruption. With these simple terms in hand, a Kos volcano tour is much easier to follow for any reader.
On a Kos volcano tour, what does a stratovolcano add?
A Kos volcano tour makes more sense once the word stratovolcano is clear. A stratovolcano is also known as a composite volcano. A volcano is an opening in the earth’s crust where melted rock, called magma, can reach the surface.
Readers planning a Kos volcano tour can start with the name. The name composite volcano reflects layers that are mixed and uneven rather than neat. Unlike a shield volcano, which is wide with gentle slopes, a stratovolcano is marked by a summit crater. A crater is the opening at the top.
Stratovolcanoes at subduction zones erupt explosively because their magma is too viscous for gases to escape easily. Viscous means thick and sticky, much like cold honey. The term subduction zone names a place where one crustal plate slides under another. Both terms are useful background for any Kos volcano tour.
Subduction zone volcanoes form as water-bearing minerals are pulled down into the mantle. The mantle is the rock layer below the crust. The water released lowers the mantle’s melting point by 60 to 100 °C. Rising magma absorbs silica-rich crust rock, which gives it an intermediate composition.
Teide in the Canary Islands and Pico do Fogo in Cape Verde are stratovolcano examples. Ol Doinyo Lengai in Tanzania and Longonot in Kenya are East African Rift examples. A rift is a long zone where the earth’s crust pulls apart. Anyone choosing a Kos volcano tour can use these names for comparison.
- Continental arcs: Stratovolcanoes form in volcano chains on land, like the Cascade Range, the Andes and Campania.
- Island arcs: Stratovolcanoes also form in island chains, such as Japan, the Philippines and the Aleutian Islands.
- Ocean islands: Stratovolcanoes can also form on oceanic islands far from plate boundaries.
Pyroclastic surges are fast clouds of ash and rock. They buried Pompeii and Herculaneum under ash and pumice 6–7 meters deep. Pumice is a very light volcanic rock. That history shows why clear terms matter on any Kos volcano tour.
On a Kos volcano tour, what does a pyroclastic flow add?
A Kos volcano tour gains a useful new term in the pyroclastic flow. It is a current of volcanic material that moves along the ground away from a volcano. It is also known more broadly as a pyroclastic density current.
Anyone reading about a Kos volcano tour can begin with speed, an easy first topic. It depends on three things: how dense the flow is, the volcanic output rate, and the slope gradient. Output rate means how fast the volcano pushes material out. Gradient means how steep the slope of the ground is.
The average speed of a pyroclastic flow is 100 km/h. The unit km/h means the number of kilometres covered in each hour. Because the figure is only an average, separate flows move faster or slower than it does. That is useful background for anyone who is planning a Kos volcano tour.
An eruption is the moment when a volcano sends its material up and out of the earth. Much of the erupted mixture sinks down to the ground because it is denser than the atmosphere. The atmosphere is the layer of air around the planet, and dense means tightly packed for its size.
Specifically, the name pyroclastic flow is used for the denser parts of a pyroclastic current. A current is the whole moving stream of material, and the flow is only its denser, heavier part. Anyone reading up before a Kos volcano tour can keep this small difference in mind.
- Surges: The lighter parts of a pyroclastic current are known as pyroclastic surges.
- Top speed: Pyroclastic flows can move as fast as 700 km/h.
- History: The 1902 eruption of Mount Pelée destroyed the town of St. Pierre on Martinique.
A pyroclastic flow adds one more word to the topic, and that word is ignimbrite. The process can lead to the production of a rock called ignimbrite. Readers who meet that word before a Kos volcano tour at least know it names a rock.
On a Kos volcano tour, what does the Volcanic Explosivity Index add?
A Kos volcano tour gains a simple yardstick from the Volcanic Explosivity Index, or VEI. This scale gives each eruption a size number. Very different eruptions can then be compared side by side, in plain terms and at a glance.
Christopher G. Newhall and Stephen Self devised the scale in 1982. A reader planning a Kos volcano tour can trace each VEI number back to three clues. The clues are the volume of erupted material, the height of the eruption cloud, and qualitative observations. The last are plain descriptions of what observers noted.
The word eruption means that a volcano ejects ash or lava, which is melted rock. The scale is open-ended, with no fixed upper limit. The largest eruptions in history are given magnitude 8. At the low end, 0 goes to non-explosive eruptions. These are defined as ejecting less than 10,000 cubic metres.
Each step up the scale is a tenfold increase in the observed material thrown out. Index 8 stands for a supervolcanic, or extremely large, eruption. It can eject 1.0×10^12 cubic metres of tephra, which is rock and ash. That ladder lets anyone weighing a Kos volcano tour compare eruptions.
About 40 VEI-8 eruptions have been identified in the last 132 million years. The latest VEI-8 eruption was Lake Taupō’s Oruanui eruption, over 27,000 years ago. At least 10 VEI-7 eruptions have occurred in the last 11,700 years. These counts give anyone curious about a Kos volcano tour a long view of eruptions.
- Records: By 2010, the Smithsonian’s Global Volcanism Program had assigned a VEI to 7,742 eruptions.
- Low values: About 49% of those eruptions have a VEI of 2 or lower.
- Material: The VEI treats ash, lava and lava bombs, which are blobs of thrown lava, alike.
The index ignores power output, which makes prehistoric eruptions extremely difficult to rate. A VEI number is therefore a measure of size, not of power output. For anyone reading about a Kos volcano tour, the scale is a start, not the full picture.
What questions arise about a Kos volcano tour?
A Kos volcano tour belongs to an island with its own international airport. Weather figures from a named station show how the seasons compare through the year. A regional unit named Kos holds two municipalities, and the Aegean Sea lies around the island.
Which airport serves a Kos volcano tour?
Kos International Airport is the international airport that serves the Greek island of Kos. An international airport handles flights between countries. It lies close to Antimachia Village. The airport is named for Hippocrates, which means it honours him, and carries the title Ippokratis.
Which season suits a Kos volcano tour?
At the Kos Sewage Plant weather station, April’s average low is 12.9 °C. At the Kos Sewage Plant weather station, September’s average high is 28.5 °C. The weather station at the Kos Sewage Plant records an October average low of 19.6 °C. Each figure is a monthly average.
Which regional unit holds a Kos volcano tour?
The Kos regional unit has two municipalities, Kos and Nisyros. Regional units, municipalities, provinces and prefectures are all government areas of different size. Within the Dodecanese Prefecture, the province of Kos counted as a single province. The Dodecanese comprises 15 major islands, including Kos, and 93 smaller islets.
Which sea lies around a Kos volcano tour?
The Aegean Sea is an elongated embayment of the Mediterranean Sea. Elongated means long, and an embayment is a bay. The Turkish name for the sea is Ege Denizi, derived from the Greek name. The Icarian Sea contains the islands of Samos, Cos, Patmos, Leros, Fournoi Korseon and Icaria.