SIO 50 Final Exam

Where are most earthquakes occurring on Earth?

Along plate edges and along faults

What are the different types of waves involved in an earthquake?

Body Waves: Primary and Secondary Waves. Surface Waves (Rayleigh and Love)

What is an aquifer?

Body of saturated rock through which water can easily move

Water table

Boundary between saturated and unsaturated zone

What is the geologic time scale? Know how it is structured (eon, era, etc.)

Calendar of Earth's history Subdivides geologic history into units. Originally made using relative dates Eon-> Era -> Periods -> Epochs

Earthflow

Downslope viscous flow of fine-grained materials that have been saturated with water

Anthropogenic Climate Change

Increases in CO2, CH4, NOx

Four largest reservoirs of water on the Earth

Oceans. Glaciers. Groundwater. Freshwater lakes.

Factors that determine porosity and permeability in an aquifer

Porosity is determined by shape of particles (well rounded particles have greater porosity than angular), packing (more closely packed -> lower porosity) Sorting (The more sorted the higher the porosity) Permeability: Tighter packing and smaller particles = less permeability Looser packing and larger particles = more permeability

What is the difference between porosity and permeability?

Porosity: Measure of how much of a rock is open space Permeability: Measure of the ease with which a fluid can move through a rock

Original Horizontality

Sediments are deposited as essentially horizontal beds

Debris flow

Turbulent flow of large rocks such as cobbles/boulders

Anticline vs Syncline

Anticline is like an ant hill Syncline is like a smile

Ecological overshoot. How is it associated with population?

Carrying capacity is diminished when consumption exceeds carrying capacity. Results in rapid population decline and ecological degradation. Human population is expanding faster than what we can account for.

Know the two types of weathering: Physical and chemical. And how they work

Chemical: Minerals in a rock are chemically altered or dissolved Physical: Mechanical breakup or fragmentation.

What is the stratigraphic record?

Chronological record of the geologic history of a region Preserved as vertical set of strata Includes sedimentary and extrusive igneous rocks

Domes and basins

Circular structures resulting from ductile deformation Domes: Broad circular or oval upward bulge of rock layers. Rock layers of a dome tilt away from the center. Domes form uplift in center, as if from an igneous intrusion. Oldest formation is in the center Basins: Broad circular or oval downward sag of rock layers. Rock layers of a basin tilt toward the center. Basins form from subsidence in the center of the basin. Youngest formation is in the center.

Understand hydrologic cycle. Its components. How it works

Circulation of Earth's water supply. Evaporation, Precipitation, Infiltration, Runoff, Transpiration, Storage in Lakes and Underground.

What is problem with radiometric dating?

Closed system is necessary Great for igneous rocks OK for metamorphic rocks (Metamorphism resets the clock) Not as good for sedimentary b/c they are aggregates

What is soil? What are the components of soil

Combination of regolith (Solid Earth materials that have been altered by processes), organic matter (humus), water, air. Capable of supporting rooted plant life

Understand why a volcano erupts and what factors influence how violent an eruption will be

Composition (Mafic vs. Felsic) Viscosity Volatile Content Mafic is low viscosity, Felsic is thick

Confined vs. Unconfined aquifer

Confined exists where groundwater is bounded between layers of impermeable substances like clay or dense rock. When tapped by a well, water in confined aquifers is forced up. Unconfined: Water table is at or near atmosphere pressure and is the upper boundary of the aquifer.

What are Milankovitch cycles?

Cycle of Earth movement around the sun. Eccentricity of Earth's Orbit (Shape of it's orbit) Obliquity (Changes in Axis tilt) Precession (wobble of axis)

Types of deformation and forces involved

Ductile is plastic. Folding, Stretching, Shearing Brittle breaks. Reverse, Normal, Strike-slip Faulting. Elastic deforms then returns to original. Sort of like ductile but less severe.

Superposition

Each layer of stratified rock in an undisturbed sequence is younger than the one beneath it and older than the one above it

Eruption Styles

Effusive: Low viscosity. Mafic composition. High temperatures. Low volatiles. Associated w/ shield volcanoes Explosive: High viscosity. Felsic composition. Low temperatures. High volatiles. Composite/Strato volcanoes

Eons and Eras

Eons = Hadean -> Archean -> Proterozoic -> Phanerozoic (Visible life: About 540 million years ago) Eras (Phanerozoic) = Paleozoic -> Mesozoic -> Cenozoic

Understand various components of faults

Faults form from brittle deformation. Normal and Reverse (Generated by Tension and Compression). Strike-slip (Generated by shearing). Head wall and Hanging Wall. Head wall goes down in normal fault, up in reverse. Thrust fault: Low-angle reverse faults where layers are thrust up and over other rocks

What's the difference between focus and epicenter?

Focus is underground. Epicenter is right above the focus

Understand various components of folds

Fold Axis is imaginary straight line parallel to hinge line of the fold. Axial plane is the plane defined by connecting fold hinge lines in multiple folded surfaces. Fold limb is the side of a fold and fold hinge is the line that separates the two limbs

Faunal Succession

Fossils entrapped in sedimentary rock layers succeed each other vertically in a specific sequence

Why is soil important to society?

Foundation of getting food. Need it to sustain agriculture.

What are some of the present-day climate issues? Why are they happening?

Global temperatures have risen 1.7 degrees F Sea surface temp have risen at 0.13 F per decade Greenhouse gas levels in atmosphere have increased Glaciers and snow is declining Sea ice is declining Ocean acidity is increasing Precipitation and weather patterns have changed

Why do changes in Earth's orbit affect climate?

If it's closer then it's hotter. If it's farther then its colder

What is the greenhouse effect? Be able to describe how it works

Incoming short-wave solar radiation penetrates atmosphere and heats Earth's surface Objects on Earth's surface reflect the long-wave radiation skyward. Greenhouse gasses absorb outgoing, long wave radiation and reradiate it Earthward, trapping the heat

How do we use fossils in stratigraphy? What is an index fossil?

Index fossil: Fossil that is particularly prevalent during a time period. Thus, it can be used as a marker in stratigraphy

Unconformities

Indicates missing time in geologic record 3 Types of Uncomformities Disconformity: 2 horizontal beds separated by an unconformable surface (erosion or non-deposition) Nonconformity: Sedimentary beds overlie an uncomformable surface on igneous or metamorphic rocks Angular Unconformity: Flat sedimentary layers overlie an unconformable surface with angled layers beneath

Why are increasing concentrations of CO2 an issue?

It's a greenhouse gas *****. Starts a positive feedback loop with Earth's environment that results in more CO2

What is a tsunami? How does a tsunami form? (What generates tsunamis?)

Japanese word for large harbor waves ; energy-driven waves. Triggered by Earthquake below or near sea level. Submarine volcanic explosion. Landslide. Asteroid impact.

What is karst?

Kart is a landscape. Characterized by limestone rocks, good groundwater circulation, and a lot of precipitation that's slightly acidic. As time passes, the acidic groundwater slowly dissolves the limestone and eventually creates cave systems. Sinkholes occur when caves get too big and get too close to the surface. The lack of support causes collapse of the roof and makes a sinkhole.

Why does subsidence occur?

Land is resting on groundwater. As groundwater gets taken out, the levels fall and rock compacts due to the pressure.

What can YOU do to live more sustainably? Why should you?

Live sustainably. Balance economic development and environmental health. Drive less and smarter. Light smarter. Use Less energy. Love Trees. Turn off the tap. Eat less meat. Eat less fish. Go organic.Buy local. Consume less. Landscape greener.

Rockslide

Material collapses en masse and moves downslope as a single laminar flow unit

Surface Waves

Produced when seismic waves reach the surface Horizontal and vertical ground movement. Horizontal and vertical ground movement. Slower than P and S waves.

Primary Waves

Push-Pull Waves. Fastest Seismic Waves. Propagate through: solids, liquids, gases

Discharge and Recharge

Recharge is downward movement of groundwater. Discharge is upward movement.

Difference between relative and absolute dating

Relative dating: Non-specific ages and comparison. This is older than this. Absolute dating: Specific ages of materials are calculated using radiometric dating techniques

Law of Inclusions

Rock containing the inclusion is younger

Rockfall

Rock falls freely from a cliff face

How do we measure and record earthquakes?

Seismograph: Device that records seismic wave motion. Seismogram: Paper record of shaking

Secondary Waves

Shear Waves. Shake particles at right angles to their direction of travel. Up and down or side to side motion. Temporarily changes the shape of a material Second fastest seismic wave. Propagates through solid material only.

Volcanic Edifices: How are they different?

Shield Volcano: Made of lava flows. Huge structure (Massive width to height ratio) Looks like a roman shield on it's side Cinder Cone: It's like an ant hill. Has a crater in the middle. Glassy volcanic fragments that accumulate around and downwind from a volcanic vent Composite volcano (Stratovolcano): Cone shaped structure with steep slopes. Alternating layers of pyroclastic material and high-viscosity degassed lava flows.

Slump

Slipping of coherent rock material along curved surface of a decline

Creep

Slow downslope movement of particles that occurs on every slope covered with loose, weathered material

Determine strike-slip motion

Stand perpendicular to fault and see which direction a landmark has been displaced. Right lateral or left lateral?

Lateral Continuity

Strata often form in laterally extensive horizontal sheets. Subsequent erosion dissects once continuous layers

Understand what strike and dip is and what it tell us

Strike: Azimuth of a horizontal line contained within a plane. Always perpendicular to dip direction Dip: Angle at which a bed is inclined from the horizontal. Always perpendicular to strike direction.

Terms to Know: Angle of repose. Turbulent/Laminar flow. Subsidence

Subsidence: Sinking of Earth's surface Angle of repose: Resting slope of materials Turbulent/Laminar flow: Type of flow. Laminar is streamline. Turbulent is complex flow.

What are some natural causes of climate change

Sunspot cycles Plate tectonics Changes in ocean currents Atmospheric contaminants Changes in Milankovitch cycles

Lahar

volcanic mudflow

Causes of Mass Wasting Events

Type of Material (Consolidated vs Unconsolidated) Water Content (Saturated vs. Unsaturated) Steepness of Slope Vegetation

Mud flow

Type of landslide characterized by large flows of mud and water

Unsaturated zone vs. Saturated zone

Unsaturated zone (right below ground level) contains water and air in the open spaces or pore. Saturated zone in which all pores and rock fractures are filled with water.

Understand radiometric dating and know basic concepts

Used to calculate ages or dates in specific number of years. Calculated using ratio of parent isotopes to daughter isotopes Radioactive atoms are unstable and decay to form different atoms at set rates OG isotopes are called parent and new one is called daughter Half life is decay rate of radio-isotopes. =Time it take for 1/2 of parent isotopes to decay into daughter isotopes

What is an earthquake?

Vibrations of the ground created by the sudden release of energy accumulating in deformed rocks

Know what viscosity is and how it affects eruption style

Viscosity: A material's resistance to flow (a function of above factors) Low viscosity -> Passive eruption High viscosity -> Explosive eruption

Cross-Cutting Relations

Whatever is cutting is younger and whatever is cut or offset is older

How do we classify mass wasting events?

When driving force exceeds resisting forces

What are the different scales used in quantifying earthquakes and how do they differ?

Mercalli: Qualitative. Based on relative destruction. Richter: Quantitative. Based on amplitude on seismogram Moment Magnitude: Quantitative. Estimates total energy released; based on displacement in fault zone

What is a fossil fuel? What are the 3 types of fossil fuels?

Natural form of energy formed in the geological past from the remains of living organisms. Coal, Natural Gas, Petroleum.

What is a cone of depression

Occurs when groundwater is pumped from a well. Depression of water layers surrounding well hole

What are some environmental issues associated with fossil fuels?

Oil spills, Oil fires, Harmful effects to environment, Increased CO2 production, Destruction of natural environments, etc.