Earth Science

• Earth Science


  A branch of physical science that deals with the study of the entire earth, its solid, liquid and gaseous part
• Branches of Earth Science

  • Geology
  • Meteorology
  • Astronomy
  • Hydrology
• Geology


  • Deals with the solid matter that makes up Earth
  • Physical Geology - concerned with understanding the composition of the Earth and the physical changes occurring in it
  • Historical Geology - deals with the history of the geological Earth and its life form through fossils
• Meteorology


  • The study of the atmosphere. Deals with the structure, composition, and the changes happening in the atmosphere
  • Includes the study of weather patterns, clouds, hurricanes, and tornadoes
  • Has a branch called climatology that studies the past and present climate
• Astronomy


  • Deals with the study of heavenly bodies. Deals with star and planets - their size, composition, structure and movements
• Hydrology


  • Deals with the circulation and distribution of water in the different spheres of the Earth
  • Oceanography - branch that studies all the aspect of ocean
• Earth's Spheres


  • Geosphere - land forms
  • Hydrosphere - water forms
  • Atmosphere - air
  • Biosphere - life

  
• Earth


  • Blue planet, Latin name: Terra, Greek name: Gaia/Gaea
  • Formed around 4.5 billion years ago
  • Third planet from the Sun and the only planet that can sustain life
  • Home to millions of species including humans
  • Percentage of land is 29%, water is 71% (97% salt water, 3% freshwater)
  • Shape is an oblate spheroid
  • Axis is an imaginary line running through the center of the earth from the North Pole to the South Pole, tilts at 23.5º
  • Total surface area of about 510.1 million km², 149 million km² stand above sea level as continents and islands

  
• Earth's Hemispheres


  • Earth has four hemispheres: northern, southern, western and eastern
  • Equator is the imaginary line around the middle of the Earth's surface that separates northern and southern hemispheres

  
• Revolution


  1. Movement of the earth around the sun

  2. Orbit of the earth around the sun is an ellipse, thus it varies

  3. Earth revolves around the sun for 365 1/4 days
• Rotation


  1. Movement of the earth with its axis

  2. Axis is an imaginary line from the top to the bottom holes of the earth

  3. Earth rotates from west to east on its axis and makes one complete rotation in 24 hours, causing the day and night
• Geology


  The science that deals with the study of solid Earth, the rocks of which it is composed and the processes on it
• Structure and Composition of the Earth

  • Earth has three distinct layers: the crust, the mantle, and the core
  • Lithosphere - the strong rigid layer composed of the uppermost mantle and the overlying crust
• Crust


  • The light, thinnest and outermost rocky layer of the earth
  • Oceanic crust - lies beneath the ocean floor and the thinnest part, mostly composed of different types of basalts
  • Continental crust - the crust that underlies the continent, made up of mostly granite
• Mantle


  • The second layer of the earth that lies below the crust
  • The thickest layer and much denser than the crust
  • Makes up about 84% of Earth's volume, made up of mostly solid material
  • Made up of iron and magnesium silicate
• Core


  • The inner, middle layer that is made up of iron-nickel alloy and is divided into inner and outer core
  • The outer core is located right below the mantle which is liquid in form
  • The inner core is in the very center which is made up of solid because of the high pressure in it
• Rock


  A naturally-occurring solid composed of one or more minerals aggregated together that covers large areas of the earth
• Rocks


  • Classified by origin, mineral composition, texture and color
• Petrology


  The study of rocks that determines the formation, composition, and structure of rocks
• Igneous rock


  The most common type of rock that is formed from molten rock (magma) that flows out from a volcano, cools down and solidifies on the earth's surface

  
• Intrusive rocks


  • Rocks formed when magma is intruded into the existing rock of the earth's continental crust, forming deep within the crust
  • Example: Granite

  
• Extrusive rocks


  • Rocks formed when magma is extruded onto the surface of the continental or oceanic crust, cooling down and solidifying quickly
  • Examples: Basalt, Pumice, Obsidian

  
• Sedimentary rocks


  Rocks formed from pre-existing rocks or pieces of once-living organisms that have been carried away from their source by water or wind and hardened/packed together
• Types of sedimentary rocks

  • Clastic sedimentary rocks (formed from clasts of pre-existing rock)
  • Chemical sedimentary rocks (formed from precipitation or evaporation of minerals from water)
  • Organic sedimentary rocks (containing large amounts of organic molecules or remains of once living organisms)
• Clastic sedimentary rocks


  • Claystone, sandstone, siltstone
• Chemical sedimentary rocks


  • Limestone, rocksalt, gypsum
• Organic sedimentary rocks


  • Rocks containing fossils
• Metamorphic rocks


  Rocks formed when igneous rocks and sedimentary rocks undergo physical and chemical changes due to heat and pressure, resulting in tearing, stretching and mashing of the minerals

  
• Types of metamorphism


  • Contact metamorphism (surrounding parent rock is metamorphosed by high temperature of intruding magma)
  • Regional metamorphism (parent rock affected by high pressure and temperature during large scale mountain building)

  
• Rock cycle


  The process by which rocks may be changed from one form to another - igneous to sedimentary to metamorphic and back to igneous

  
• Rock cycle

  1. Igneous rocks form from cooling magma

  2. Igneous and sedimentary rocks weather into sediments

  3. Sediments are deposited in layers and hardened into sedimentary rocks

  4. Sedimentary rocks may be buried and metamorphosed into metamorphic rocks

  5. Metamorphic rocks may melt back into magma, completing the cycle

  
• Earthquake


  Sudden movement of the ground caused by too much stress building up in the rocks that the rocks tend to rupture
• Seismograph


  Instrument used to detect and record earthquakes vibration

  
• Seismologists


  Scientists who study earthquakes
• Types of earthquake


  • Tectonic earthquake
  • Volcanic earthquake
  • Collapse earthquake
  • Explosion earthquake

  
• Tectonic earthquake


  Earthquake that occurs due to forces created by the movement of tectonic plates

  
• Volcanic earthquake


  Earthquake that occurs in conjunction with volcanic activity

  
• Collapse earthquake


  Small earthquakes in underground caverns and mines
• Explosion earthquake


  Earthquake that results from the explosion of nuclear and chemical devices
• Anatomy of an earthquake

  • Focus or Hypocenter
  • Epicenter
  • Fault
  • Seismic waves