Get our newsletter!
Check out our volcano tours on VolcanoAdventures.com!
Volcanoes & Earthquakes - new app for Android
Guaranteed tours
8-16 May 2021: From Stromboli to Etna - Sicila and Eolian Islands (Italy)
: spaces available / : guaranteed / : few spaces left / : booked out

Geology glossary

Search for term:

< Previous  Page 1  Page 2  Page 3  Page 4  Page 5  Page 6  Page 7  Page 8  Page 9  Next >

sediment

Geology
Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of water or other liquid.
Sediments are also transported by wind (aeolian processes) and glaciers. Desert sand dunes and loess are examples of aeolian transport and deposition. Glacial moraine deposits and till are ice transported sediments. Simple gravitational collapse also creates sediments such as talus and mountainslide deposits as well as karst collapse features. Each sediment type has different settling velocities, ... -> See whole entry

seismograph

Earthquakes
A seismograph at a volcano observatory in Indonesia
A seismograph at a volcano observatory in Indonesia
Seismic recording on a drum
Seismic recording on a drum
An instrument that displays vibrations and movements in the Earth = the recording of a seismometer.
Traditional seismographs transfer the recorded shaking to a precise pencil that writes a continuous shake line onto a sheet of paper wrapped around a turning drum.

The drum slowly turns at steady speed and at the same time, the pencil is slowly moved horizontally, so that the line forms a continuous spiral line on the paper until it is filled. Each turn of the drum (or each line on the unwrapped... -> See whole entry

shield volcano

Volcanology
Mauna Loa shield volcano (Big Island, Hawaii)
Mauna Loa shield volcano (Big Island, Hawaii)
A large shield volcano in the Danakil desert (Ethiopia)
A large shield volcano in the Danakil desert (Ethiopia)
Shield volcanoes are volcanoes that mainly erupt fluid (usually basaltic) lava flows that are able to travel over long distances and thus construct over time broad, gentle slopes. They are called shield volcanoes, because they resemble the shape of a warriors' shield.
Shield volcanoes are volcanoes that mainly erupt fluid (usually basaltic) lava flows that are able to travel over long distances and thus construct over time broad, gentle slopes. They are called shield volcanoes, because they resemble the shape of a warriors' shield.

While stratovolcanoes, the other major morphological type of volcanoes, are representative for most subduction-type volcanoes, sh... -> See whole entry

skylight

Volcanology
Skylight on Etna volcano (Italy)
Skylight on Etna volcano (Italy)
Skylight on Etna volcano (Italy)
Skylight on Etna volcano (Italy)
Skylights are openings in the roof above a lava tube, from where the flowing lava flow can be seen. Usually, these holes are caused by the simple collapse of the roof of the tube.

Related keywords (1):

Coulée de lave

smoke ring

Volcanology: volcanic smoke ring, gas ring, steam ring
Etna's Bocca Nuova crater in 2000, emitting smoke rings
Etna's Bocca Nuova crater in 2000, emitting smoke rings
Smoke ring detail (Etna)
Smoke ring detail (Etna)
A rare phenomenon, where a visible vortex ring of steam and gas is expelled from a volcanic vent.
Under special conditions, gas and steam expelled from a vent can form gas rings. It probably requires a particular geolometric configuration of a circular vent exit, as well as expulsion of gas in individual puffs with just the right velocity.

This phenomenon is quite rare, but has been witnessed at several volcanoes, including Stromboli and Etna. At Etna, a spectacular period lasting several mo... -> See whole entry

strombolian eruption

Volcanology
Strombolian eruptions from vents of Stromboli volcano, Eolian Islands, Italy
Strombolian eruptions from vents of Stromboli volcano, Eolian Islands, Italy
Strombolian eruption from Yasur volcano, Vanuatu
Strombolian eruption from Yasur volcano, Vanuatu
Strombolian eruptions are the smallest type of explosive eruptions. Strombolian eruptions consist of intermittent, generally relatively small explosions or weak pulsating fountains of fluid (usually basaltic) lava from a single vent or crater. They are called so after the type locality of Stromboli volcano (Eolian Islands, Italy), which has been in strombolian activity for probably more than 2000 years.
An individual strombolian explosion is the result of sudden release of volcanic gasses. The typical rhythmic occurrence is caused by gradual accumulation of gas bubbles beneath a weakly solidified plug at the top of the magma column at the vent surface until the gas pressure is high enough to erupt through it, ejecting with it both solid and liquid spatter from the magma. -> See whole entry

tectonic

Earthquakes
The adjective "tectonic" refers to processes, properties, or resulting features related to the deformation (breaking and slow, plastic deformation) of rocks over large sections of the upper mantle and crust (lithosphere). It is usually applied to large-scale features and processes, in the km scale and app. Smaller miniature tectonic processes are sometimes called micro-tectonic.

tectonic faultSynonym of: fault

Earthquakes
Illustration of the main types of tectonic faults (source: USGS)
Illustration of the main types of tectonic faults (source: USGS)

tephrite

Volcanology
Tephrite is an type of volcanic (extrusive) rock with low silica content, similar to basalt, but containing foid minerals (e.g. nephelinite, leucite) along with plagioclase. The composition of tephrite is called tephritic.

tephritic

Volcanology
Tephritic refers to the mineral composition of tephrite, an type of volcanic (extrusive) rock with low silica content, similar to basalt, but containing foid minerals (e.g. nephelinite, leucite) along with plagioclase.

< Previous  Page 1  Page 2  Page 3  Page 4  Page 5  Page 6  Page 7  Page 8  Page 9  Next >

 

More on VolcanoDiscovery

 
Why is there advertising on this site?
Copyrights: VolcanoDiscovery and other sources as noted.
Use of material: Most texts and images, in particular photographs, on this website are protected by copyright. Further reproduction and use of without authorization is usually not consented. If you are not sure or need licensing rights for photographs, for example for publications and commercial use, please contact us.
Home | Travel | Destinations | Volcanoes | Photos | Earthquakes | About | Glossary | News | Contact | Privacy | Imprint || Français | Deutsch
Follow us: