Grading Breakdown: The lecture portion is 60% of your grade (45% from the best 3 of 4 exams; 15% from iClicker, Connect, and quizzes). The lab portion is 40% (10 labs and 3 lab exams), and everything in lab counts.
Lecture Exam 1 Details: This exam is online, consists of 50 multiple-choice questions, and has a 50-minute enforced time limit. It is open-note but must be completed individually.
Attendance: Attendance is expected for lecture; iClicker points are earned daily. Lab attendance is mandatory.
II. Earth Structure
Earth Systems: Physical geology includes the study of the Solid Earth (surface and interior), Water (oceans, fresh water, ice), Atmosphere, and Biosphere.
Compositional Layers (What it is made of):
Crust: The thin, outermost shell.
Mantle: The largest volume, divided into Upper and Lower Mantle.
Core: Divided into a Liquid Outer Core and a Solid Inner Core.
Mechanical Layers (How it behaves):
Lithosphere (0–100 km): Mechanically strong and rigid; it breaks (brittle) under stress.
Asthenosphere (100–200 km): Mechanically weak and partially molten (~2%); it flows (ductile) like silly putty.
III. Plate Tectonics
Plate Boundaries:
Divergent: Plates move apart. Features include mid-ocean ridges (spreading centers) and continental rifts.
Convergent: Plates move toward each other. Features include subduction zones (forming trenches and volcanic arcs) and continental collisions (forming large mountain belts).
Transform: Plates slide horizontally past one another (e.g., the San Andreas Fault).
Evidence for Motion:
Magnetic Stripes: New oceanic crust records magnetic reversals (flipping of Earth’s polarity) symmetrically on either side of mid-ocean ridges.
Seafloor Age: The youngest rocks are at the ridges, and the oldest are farthest away.
Mantle Convection: The movement of tectonic plates is driven by escaping heat from the Earth’s interior (leftover from early impacts, gravitational contraction, and radioactive decay). Hotter, less dense material rises, while cooler, denser material sinks.
IV. Earthquakes
Key Definitions:
Hypocenter (Focus): The 3D location in the Earth where the earthquake begins [Previous Response, 43].
Epicenter: The location on the surface directly above the hypocenter [Previous Response].
Seismic Waves:
Body Waves: Pass through Earth’s interior. P-waves (primary) are the fastest and travel through solids and liquids. S-waves (secondary) are slower and cannot travel through liquids.
Surface Waves: Travel along the surface and typically cause the most damage.
Magnitude vs. Intensity:
Magnitude: Measures the total energy released; it is a fixed value for a single event. Each whole number increase represents a 32-fold increase in energy.
Intensity: Measures the severity of shaking felt at a specific location; it varies based on distance and ground type (soft soil shakes more than hard rock).
Imaging the Interior: Seismologists use shadow zones to prove the outer core is liquid (because S-waves cannot pass through it). Seismic tomography creates 3D images where “fast” areas are cold/dense and “slow” areas are warm.
V. Rock Deformation
Stress and Strain:Stress is the force applied per area; Strain is the rock’s response (change in shape or volume).
Deformation Styles:
Brittle: Rocks break or fracture; occurs at shallow depths where it is cold.
Ductile: Rocks flow or bend; occurs at deeper conditions where it is hot and under high pressure.
Brittle-Ductile Transition: Occurs at approximately 30 km depth.
Faults (Fractures with offset):
Normal Fault: Caused by tensional stress (pulling apart); the hanging wall moves down.
Reverse/Thrust Fault: Caused by compressional stress (squeezing); the hanging wall moves up.
Strike-Slip Fault: Caused by shear stress; movement is horizontal (left-lateral or right-lateral).
Folds (Bending of layers):
Anticline: Warped upwards (like an “A”); the oldest rocks are in the center.
Syncline: Warped downwards (like a “U”); the youngest rocks are in the center.
Monocline: A step-like fold often “draped” over a deeper fault.
Mountain Building: Mountains are created by orogeny. This can involve crustal shortening (compression) or mantle upwelling (extension, like the Basin and Range). Regional elevation is controlled by crustal thickness, density, and temperature [Previous Response, 78].