Exam 2 Flashcards
What is a volcano?
Cone or shield shaped mountain formed at vent from which molten rock and/or gases reach the earth’s surface and erupt
What’s the difference between magma and lava?
Magma: molten rock within the earth
Lava: magma that reaches the surface
How could rock melt?
Adding temperature or adding water
What is viscosity?
How fluid magma is. Different silica content determines high or low viscosity. High silica –> high viscosity
HIGH VISCOSITY: thick and pasty magma
LOW VISCOSITY: flows easily
What are the different rock viscosity characteristics?
Basalt: brown or black. Lower viscosity (lower silica), more fluid, somewhat like cold molasses—mostly lava flows in eruptions. Least explosive
Rhyolite: white or pale shades—extremely viscous—mostly ash in eruption. Highest viscosity and volcanic danger
Andesite: viscosity between basalt and rhyolite. Most common. Flows slowly and solidifying on steep slopes.
What are the different magma properties as it solidifies?
Aa-Aa (ow, ow): sharp, jagged, uneven
Pahoehoe: Rope-like
Pillow basalt: forms as it hits water
What are the factors of the Volcanic Explosivity Index?
Size of volcano
Volume ejected material
Violence
What are the different types of volcanoes?
Cinder cone: steep-sided conical volcano characterized by loose rock fragments from eruptions. low viscosity. EXAMPLE: Mount Fox crater
Composite: upwardly concaved slope and a small summit crater. also called strata volcano. high viscosity EXAMPLE: Mount St. Helens
Shield: a broad domed volcano with gently sloping sides, characteristic of the eruption of fluid, basaltic lava. EXAMPLE: Mauna Loa (Hawaii)
Lava Dome: steep-sided mound that is formed when lava reaching the Earth’s surface is so viscous that it cannot flow away readily and accumulates around the vent. EXAMPLE: Lassen Peak
What are some hazards from volcanoes?
Pyroclastic flows: fast moving material and gas
Ash and rock fall
Mudflows
Gas outbursts and poisonous gases eg: sulfur dioxide, carbon dioxide, hydrogen fluoride
What are some impacts of volcanoes?
Climate change
Large explosions release volcanic gas, aerosol droplets, and ash into the stratosphere
Sulfur dioxide can cause global cooling; carbon dioxide can cause global warming
What are the different styles of explosions from least to most explosive?
Strombolian: expanding steam bubbles blow magma into cinders; cinders fall around the vent to form a cinder cone; LEAST EXPLOSIVE
Vulcanian: dark eruption clouds send out blocks of volcanic rock; ash falls, some pyroclastic flows, and lateral-blast eruptions
Pelean: violent rhyolite, dacite, or andesite eruptions; high columns of ash collapse to form pyroclastic flows
Plinian: powerful continuous blasts of gas; Nuée ardente (glowing gas cloud); carry pumice high into the atmosphere, including penetration into stratosphere; silicon-rich ash and pyroclastic flows; MOST EXPLOSIVE
What are the different styles of explosions from least to most explosive?
Strombolian: expanding steam bubbles blow magma into cinders; cinders fall around the vent to form a cinder cone; LEAST EXPLOSIVE
Vulcanian: dark eruption clouds send out blocks of volcanic rock; ash falls, some pyroclastic flows, and lateral-blast eruptions
Pelean: violent rhyolite, dacite, or andesite eruptions; high columns of ash collapse to form pyroclastic flows
Plinian: powerful continuous blasts of gas; Nuée ardente (glowing gas cloud); carry pumice high into the atmosphere, including penetration into stratosphere; silicon-rich ash and pyroclastic flows; MOST EXPLOSIVE
What is a continental caldera? Describe Yellowstone as one.
Rhyolitic volcanoes with high magma viscosity, high volatile content, and gently sloping flanks. Erupt in massive volume until magma chamber has emptied enough for the ground to collapse. New magma may fill up to create a resurgent dome. Eruptions are infrequent. Yellowstone is a giant continental caldera and hasn’t erupted for about 631,000 years.
What are mitigation tactics for volcanoes?
National Volcano Early Warning System (NVEWS): national scale plan to ensure volcanoes are monitored based on their potential threat through the USGS volcano hazards program.
What does the National Volcano Early Warning System seek to improve on?
Partnerships with local governments and emergency responders
Grants to universities and other research programs
Increased staffing automation to improve 24/7 monitoring
Computer systems to distribute data
What are signs of a volcanic explosion?
Seismograph records-harmonic tremor
Small earthquakes
Change in volcano surface temperature and steam indicators
Some change in slope or bulging
Change in ratio sulfur to chlorine gas
What is a landslide and how do they express themselves?
A land slide is the movement of a mass of rock, debris, or earth down a slope. They can occur as falls, topples, slides, spreads, or flows
What causes the land to move?
Rainfall, snowmelt, changes in water level, stream erosion, changes in groundwater, earthquakes, volcanic activity, disturbance by human activities, or any combination
What are quick clays?
Water saturated clays — can be triggered by heavy rains or other soil disturbance. Lattice-like structure and binds together quickly
What is the angle of repose and downslope?
Angle of repose: steepest angle at which loose sorted material is stable
Downslope: gravity pulling rock on slope vertically downward
What are the warning signs of landsides?
Springs, seeps, or saturated ground in areas that have not typically been wet before.
New cracks or unusual bulges in the ground, street pavements or sidewalks.
Soil moving away from foundations.
Ancillary structures such as decks and patios tilting and/or moving relative to the main house.
Tilting or cracking of concrete floors and foundations.
Broken water lines and other underground utilities.
Leaning telephone poles, trees, retaining walls or fences.
What are mitigation tactics for landslides?
Retaining wall
Up to date building codes
Improving drainage
Reducing angle of slope
Buttresses
What is a sinkhole and its impact?
They form when overlying ground collapses into underground soil cavities over limestone. Ground water dissolves limestone easily. Impacts include:
Damage to houses and roads
Can drain streams, lakes, and wetlands
Channel contaminants are directly introduced into groundwater
What is an aquifer?
A body of permeable rock which can contain or transmit groundwater.
What are signs sinkholes are active in an area?
Round circular depression
Localized subsidence
Circular small lake forming
Major foundation cracks
Sudden drop in well water levels
Rainwater disappearing into ground openings
Major cracks in road pavement
What is karst topography?
Karst is topography formed from the dissolution of soluble rocks such as limestone. It is characterized by underground drainage systems with sinkholes and caves.
What are the consequences of peat drainage?
Loss of plant rooting depth where the substrate is unfavorable (stony, acidic, saline)
Increased pumping for instability of roads and their structures
Increase in nutrient outflows
Colder surface temp during winter night
Increase of co2 flux to the global atmosphere
What is permafrost?
Permanently frozen layer on or under the earth’s surface. It consists of soil, gravel, and sand, usually bound together by ice. Usually remains at or below 0 C for at least 2 years.
What is solifluction?
The gradual movement of et soil or other material down slope especially where frozen subsoil acts as a barrier to the percolation of water
What is the difference between weather and climate?
Weather: atmospheric conditions and activity at a particular time and place
Climate: average weather conditions over time for a particular region of the world; usually 30-year average
Describe the two lowest atmospheric layers.
Troposphere: lowest layer, where weather happens
- Tropopause: where the troposphere ends; greatest ozone concentration
Stratosphere: 2nd lowest layer; where ozone is
What are the different atmospheric controls?
Latitude
Land and water relationships
Ocean currents and air masses
Altitude
Landform barriers/ orographic
Humans
What is wind?
The response to atmospheric pressure to remain balanced. Typically horizontal movement to a pressure gradient force
What is the difference between low and high pressure?
Low pressure: Rising air; brings ppt
High pressure: Sinking air; brings dry and sunny weather
What is the coriolis effect?
The deflection of air based on the rotation of the Earth; air is reflected to the RIGHT in the NH. The opposite is true in the SH
What is humidity?
The amount of water vapor in the air
What is the difference between specific humidity and relative humidity?
Specific humidity:
o mass of water vapor/ mass of total air
o specific amount of water vapor g/kg in the air
o Varies as low as 0.2 g/kg in dry arctic to 18 g/kg in moist equatorial regions
Relative humidity:
o A proportion/ percent the amount of water vapor present vs the amount of water vapor and air mass can hold at a specific temperature
What is the DALR and SALR?
DALR: rising dry air 5.5 F/ 1000 ft
SALR: rising saturated air 2.2-4.9 F/ 1000 F
What is fog and its types?
Fog = cloud layer at the surface
Radiation fog: at night when air layer above ground falls below the dew point. Often occurs in low lying areas
Advection: when warm, moist, air mass moves over a cold surface. Air cools and dew point is reached. Often occurs along coastal regions.
What are the major cloud types?
Cirrus
Cumulus
Stratus
“Alto”
“Nimbus”
What are the types of ppt?
Rain, snow, hail, sleet, freezing rain, grouple
What are the types of ppt?
Rain, snow, hail, sleet, freezing rain, grauple
What are monsoons and why are they dangerous?
Seasonal change in wind patterns with clear wet season and pronounced dry season. They bring tremendous amounts of rain that can cause flooding or landslides
What are the 3 ways ppt is created?
Orographic
Convective
Frontal
What is lightning?
An electric discharge in the atmosphere between oppositely charged clouds/ land.
What is El Niño and La Niña?
An unusual cooling or warming of the pacific ocean.
El Nino
o Trade winds weaken
o Warm air pushed eastward
o Southern shift jet stream
o SW US: warmer and potential for flooding
o NW US: warmer and drier
La Nina
o Strong trade winds
o Cold water upwellings off coast of S America
o SW US: drought and hot
o NW US: rainy and potential flooding
What is the EF scale? What are tornadoes and where do they occur?
The Enhanced Fujita scale is a scale that measures tornado intensity.
Tornadoes are tight columns of intensely rotating air. They occur everywhere around the world.
Top tornado state: Texas
What is the GOES satellite? How would it be used?
A tool to view a satellite image of a specific region in the west hemisphere. It’s useful to use to track cold and warm fronts and where storms may be traveling.
What is the difference between a watch and a warning?
Watch: conditions are favorable for an event to occur
Warning: the event is actively occurring either spotted on radar or it’s physically seen by storm spotters
What is the wind chill and heat index? What are the hazards of them?
Wind chill: the quantity expressing the effective lowering of air temp caused by wind, especially affecting the rate of heat loss from an object or the human body
Hazards: frostbite
Heat index: Apparent temp. what the temperature feels like to the human body when relative humidity is combined with the air temperature
Hazards: heat stroke
