Science Reviewer (Week 3-4) PDF

SCIENCE REVIEWER (WEEK 3 - 4) Internal Structure of the Earth 2 Scientific Evidences of Earth’s Interior (Based on the Researchers) 1. Seismic Waves How did Seismic Waves lead to discovery of Earth's interior? - S-Waves can only travel through solids, which helped...

SCIENCE REVIEWER (WEEK 3 - 4) Internal Structure of the Earth 2 Scientific Evidences of Earth’s Interior (Based on the Researchers) 1. Seismic Waves How did Seismic Waves lead to discovery of Earth's interior? - S-Waves can only travel through solids, which helped scientists understand the different layers within the Earth. 2. Rock Samples 3 Major Layers of Earth 1. Crust - 0.5% of Earth's Mass - Continental: composed of granitic and sedimentary rocks - 30-50 km oe 20-30 mi - less dense - older because they are rarely destroyed - Oceanic: Composed of basaltic and Igneous rocks -6-7km or 5-7 mi - more dense and younger - Litosphere: where tectonic plates are located - brittle and rigid Mohorovicic Discontinuity - where seismic waves changes velocity - boundary between crust and mantle - discovered by Andreaha Mohorovicic in October 8, 1909 Project moho (1958): project which aims to get a sample of earth's crust - started 1958 - drilling started in 1960 - only stopped til the crust - conducted by american miscellaneous society - was conducted in guadalupe mexico discontinued due to: 1. political issues 2. budget issues 3. scientific issues 2. Mantle - 80% of Earth's Mass - minerals that can be found are Fe, Mg, Al, Si, and O - Asthenosphere - from the Greek word “asthenes” meaning without strength. - plasticity characteristic - Upper Mantle  SCIENCE REVIEWER (WEEK 3 - 4) - Middle Mantle - Lower Mantle Gutenburg Discontinuity - between mantle and core - where seismic waves changes velocity - discovered by Weichert Gutenburg in 1912 3. Core - innermost layer of the Earth - Composed of the outer core and inner core, together making up about 15% of Earth's volume. - The inner core is solid, The outer core is liquid and composed of Fe and Ni. As you go DEEPER, TEMPERATURE and PRESSURE increases - celsius temperature 1 DEGREE = 40 METERS Oceanic is YOUNGER than Continental Oceanic Rocks - basaltic and igneous -> Continental is older because it is rarely destroyed or recycled Ionian Sea and Mediterranean Sea: existing oceanic crust but still younger than continental - most of the rocks: oceanic & existing old rocks  SCIENCE REVIEWER (WEEK 3 - 4) Earthquake - produced by sudden release/snap off energy - shaking or trembling caused by release of energy - usually associated with faulting or breaking of rocks Where do Earthquakes occur and How often? 90% - Pacific Ring of Fire most of these result from convergent margin activity 15% occur in Mediterranean-Asiatic belt 5% occur in the interior of plates and on spreading ridge centers more than 150,000 earthquakes Top Countries Exposed to Volcanic & Seismic Activities: 1. indonesia 2. Japan 3. Philippines 4. Chile 5. Mexico 6. Kamchatka Peninsula 7. United States 8. New Zealand 9. Alaska 10. Canada Faulting - breaking of crust 1 CM - Movement per year TYPE FORCE PLATE FOCUS & MAGNITUDE NORMAL TENSION DIVERGENT SHALLOW FOCUS LOW MAGNITUDE STRIKE-SLIP SHEER TRANSFORM HIGH MAGNITUDE DEEP FOCUS REVERSE/THRUST COMPRESSION CONVERGENT DEEP FOCUS HIGH MAGNITUDE  SCIENCE REVIEWER (WEEK 3 - 4) Elastic Rebound Theory - explains how energy was made and released during earthquake - The sudden release and spread of energy - Rocks bend until the strength of the rock is exceeded - Rupture occurs and the rocks quickly rebound to their undeformed shape - Energy is release in waves that radiate outward from the fault Proponent: Harry Fielding Reid (American Seismologist) - BASIS OF THIS STUDY: 1906 San Francisco Earthquake PROCESS OF ELASTIC REBOUND THEORY Friction -› Pressure -› Force -› Energy Pacific Ring of FIRE - Subduction Zones Wadati Benioff Zone - seismological activities in the upper mantle while the lithosphere plate subducts or a planar zone of seismicity corresponding with the down-going slab in a subduction zone - zone below subduction zone - originates from: kiyoo WADATI (japanese semiologies) and hugo BENIOFF (american seismologist)  SCIENCE REVIEWER (WEEK 3 - 4) Chile Great Valdivian Earthquake - May 22, 1960 - 9.5 Magnitude - Lasted for 10 minutes Notable Earthquake of 20th Century Philippines Killer Luzon Earthquake July 16, 1990 4:26 PM 7.8 Magnitude 2000 deaths Epicenter: Nueva Ecija Tokyo Earthquake March 11, 2011 - 9.1 magnitude  SCIENCE REVIEWER (WEEK 3 - 4) Seismic Waves the shaking of the ground is caused by: ELASTIC STRAIN ENERGY (Stored Energy) CROSS SECTION OF AN EARTHQUAKE Hypocenter (HYPO): The point beneath the Earth's surface where the earthquake originates. Epicenter (EPI): The point on the Earth's surface directly above the hypocenter.  SCIENCE REVIEWER (WEEK 3 - 4) BODY WAVES Higher Frequencies and Lower Amplitude - (interior) mantle up through the core - higher frequency - arrives before the surface waves - speed is directly proportional to frequency - amplitude is inversely proportional to frequencies - stops traveling at the mantle PRIMARY WAVES SECONDARY WAVES - Compressional Waves - Shear Waves - fastest wave - perpendicular (up & down) - moves back and forth - slower than P-Waves - refracted - refracted: creates shadow REFRACTION - Slow Down and Bending of waves as they trav through layers of Earth. REFRACTED - Bended or Distorted SURFACE WAVES Lower Frequency and Higher Amplitude - traveling only through the crust - responsible for earthquakes RAYLEIGH WAVES LOVE WAVES - elliptical motion/circular - fastest s-wave - no transverse/perpendicular - horizontal motion - ripple up and down - shake from side-to-side - named after: British mathematician Augustus Edward Hough Love. PLSR - PRIMARY, SECONDARY, LOVE AND RAYLEIGH SEISMOMETER is the INNER PART OF SEISMOGRAPH SEISMOGRAM - result and it records the motion of earthquake/any gram motion  SCIENCE REVIEWER (WEEK 3 - 4) TRIANGULATION METHOD - A technique used to determine the location of an earthquake's epicenter by using data from three or more seismic stations. - Three stations are the minimum required to accurately determine the epicenter, as fewer stations would provide insufficient data.