ESS105 Study Guide: Chemical Reservoirs and Solid Earth Structure

Course title: ESS105H1 S LEC0101 20241: Our Home Planet
Term assignments: - Group term assignment: Create a ~3-minute educational video explaining an Earth science concept. - Deliverables: - Video file - Written script (includes reference list) - Video release form - Group size: 3-4 people - File submission: Upload completed assignments to OneDrive using UToronto credentials. - Due date: March 18, 11:59 PM; sign-up deadline for group – January 23.

Students must sign up for their groups on a provided Google sheet (available until Jan 23).
Instructions and supporting files are available via links: - ESS105 Term Assignment Details - ESS105 Script Template - ESS105 Term Assignment Release Form
Past examples of student videos are available on Quercus for reference.

Focus on scientific concepts, not policy or politics. - E.g., Appropriate topics include: - “How infrared absorbance by atmospheric gases affects our climate” (scientific focus). - “How oil company CEOs have ruined the Earth” (political focus, not recommended).
A rubric for grading will be posted on Quercus.
A stock footage policy: - Students are encouraged to use stock footage, with proper attribution of sources in scripts.

Students must include their full name and student number on the group registration sheet.
Groups not formed by Jan 23 will be assigned randomly.

For questions or technical issues, students should contact lead TA Ting Lei via Quercus.

Quick look at Packback posts, focusing on: - Asking open-ended questions - Including references for information.

Comparative Planetology: The use of knowledge gained from studying Earth to understand other planets. - Technologies used for Earth studies can also be applied to extraterrestrial studies (e.g., remote sensing, geological exploration, atmospheric monitoring).

Earth’s differentiation results in distinct chemical reservoirs: - Recognized reservoirs include the oceans, atmosphere, and solid Earth. - The solid Earth comprises roughly 99.977% of Earth’s total mass (> 10 billion trillion kilograms).

Mass of Earth’s Reservoirs: - Atmosphere: 5.15 x 10^{18} kg (0.00009%) - Oceans: 1.38 x 10^{21} kg (0.02311%) - Solid Earth: 5.97 x 10^{24} kg (99.977%)
The atmosphere and oceans, while small by mass, play critical roles in Earth’s evolution.
Solid Earth is differentiated into multiple reservoirs but is only partly accessible.
Deep drilling has occurred (e.g., Russia’s 1970s project), uncovering limited geological knowledge.

Seismic Waves: Main source of information about Earth’s inner structure, generated by earthquakes.
Types of seismic waves: - P waves (Primary): Longitudinal waves; fastest; can travel through solids and liquids. - S waves (Secondary): Shear waves; only travel through solids; slower than P-waves. - Love waves: Surface waves causing horizontal ground motion. - Rayleigh waves: Surface waves causing vertical and horizontal ground motion.

Wave Propagation: How seismic waves spread from the earthquake source (hypocenter).
Seismic Shadows: Areas where certain wave types do not propagate. Important for understanding core properties: - S-wave shadow zone: Indicates a liquid outer core due to S-waves not traveling through liquids. - P-wave shadow zones arise due to refraction, indicating changes in material properties.

Understanding how and why P and S wave speeds change with depth leads to insights into Earth’s composition and has implications for geology and material science.

A comprehensive model summarizing wave speeds (P, S) and density as functions of depth.
Key features: Discontinuous changes in material properties indicate layer boundaries, while gradual changes suggest pressure effects.

Differentiation is crucial for Earth’s composition and structural understanding.
Different seismic properties help delineate layers within Earth’s interior.
Continued exploration of Earth's reservoirs will follow, focusing on their specific chemistries and characteristics.