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🌍 Earth’s Interior – Short Study Notes
### 🪨 Crust
#### 📌 Composition & Thickness
- Made of Silica + Aluminium (SiAl)
- Thickness → 5–70 km
#### 🌍 Types of Crust
- Continental Crust → land part, ~30 km (thick & lighter)
- Oceanic Crust → water part, ~5 km (thinner & denser)
### 🔥 Mantle
#### 📌 Composition & Thickness
- Made of Silica + Magnesium (SiMa)
- Thickness → ~2900 km
#### 🧩 Structure
- Upper Mantle & Lower Mantle
- Top layer → Solid form
#### 🌊 Asthenosphere
- Semi-molten layer below lithosphere
- Helps in plate movement
### ⚙️ Core
#### 📌 Composition
- Made of Nickel + Iron (NiFe)
#### 🧩 Divisions
- Inner Core → Solid, ~2200 km
- Outer Core → Liquid, ~1300 km
- Responsible for magnetic properties
### ⚡ Discontinuity
- Boundaries between different layers of Earth
- Identified through seismic waves
### 🌍 Lithosphere
- Crust + Upper solid mantle
- Thickness → 10–200 km
- Asthenosphere is NOT part of lithosphere
### 🌐 Tectonic Plates
- 7 Major plates + several minor plates
- Movement occurs over asthenosphere
### 🌋 Sources of Interior Knowledge
#### 🔍 Direct Sources
- Volcanoes & rocks → provide actual material
#### 📊 Indirect Sources
- Temperature, Earthquakes, Meteorites
- Help understand internal structure
### 🌪️ Earthquake
#### 📏 Measurement Scales
- Richter Scale → measures magnitude (0–10)
- Considered limitless scale
- Mercalli Scale → measures intensity (1–11)
🧠 Memory Tricks
- “SiAl → Surface” → Crust composition
- “SiMa → Middle” → Mantle composition
- “NiFe → Nucleus” → Core composition
- “Litho = Life zone” → plates exist here
- “Rich = Power, Mercalli = Damage” → magnitude vs intensity
