Questions and Answers
Who proposed the theory that the continents moved due to tidal forces from the moon?
Which type of fault occurs when the hanging wall moves down relative to the footwall?
Reverse Faults are characterized by the hanging wall moving up relative to the footwall.
True
What is the process by which glaciers erode land?
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Elastic rebound theory states that tectonic plates move slowly and do not cause earthquakes.
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Which of the following are effects of soil erosion? (Select all that apply)
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What does a seismograph do?
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Humans contribute to soil erosion through activities like deforestation.
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The point on Earth's surface directly above the focus of an earthquake is called the ______.
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What is the largest ocean on Earth?
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Which of the following is NOT a component of the hydrological cycle?
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What is volcanic magma?
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Match the following oceanic regions with their significance:
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Which type of volcanic eruption is characterized as non-explosive?
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Climate refers to short-term atmospheric conditions.
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Match the following types of weathering with their definitions:
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______ is the measure of the amount of water vapor in the atmosphere.
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Soil erosion can occur naturally without any human influence.
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What are the components of soil?
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What does the Saffir-Simpson scale classify?
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What is an example of a cinder cone volcano?
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Which instrument measures atmospheric pressure?
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Monsoons are caused by temperature differences between land and water.
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What is the estimated age of the Earth?
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Which of the following methods is used to determine the age of rocks?
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Earth is a perfect sphere.
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What is the average radius of the Earth at the equator?
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What phenomenon causes the seasons on Earth?
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Which of the following is a type of sedimentary rock?
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What is the primary characteristic of metamorphic rocks?
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Igneous rocks are formed from the accumulation of sediments.
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The ________ is used to determine the time zones across the Earth.
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Which of the following types of maps shows the political boundaries between geographic units?
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What is the main feature of a globe?
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Which of the following minerals is known for its use in toothpaste?
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Coal is an igneous rock.
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What term describes the movement of magma to form igneous rocks?
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Who proposed the Earth Expansion Theory?
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Study Notes
Earth’s Age and Measurement
- William Thomson (Lord Kelvin) estimated Earth's age to be 20-40 million years based on cooling time from a molten state.
- Modern scientific consensus places Earth's age at approximately 4.5 billion years.
- Key techniques for determining age:
- Stratigraphy: Studies the layering of rock or sediment to ascertain relative ages.
- Radiometric dating (Carbon dating): Uses radioactive decay of elements to find the actual age of rocks and minerals.
Earth’s Size and Shape
- Earth is an oblate spheroid, flattened at the poles and bulging at the equator due to rotation.
- Equatorial radius: 6,378 km, Polar radius: 6,356 km; equatorial diameter: 12,756 km, polar diameter: 12,712 km.
- Earth's equatorial circumference is about 40,075 km, while meridional circumference is approximately 40,008 km.
How Scientists Measured Earth
- Aristotle proposed an Earth circumference of 45,000 miles.
- Eratosthenes developed calculations improving the understanding of Earth’s size.
Earth’s Motion
- Rotation: Earth rotates on its axis from west to east, at an angle of 23.5 degrees, taking about 24 hours for one complete turn.
- Revolution: Earth's orbit around the Sun takes approximately 365.242 days, at a speed of 30 km/s.
Understandings of Maps
- Maps provide a symbolic representation of geographic locations, aiding navigation and understanding of landscapes.
- Atlas: A collection of maps, with the term originating from Gerardus Mercator’s 16th-century contribution.
- Map types include:
- Political maps: Show boundaries between governments.
- Physical maps: Display natural landscape features.
- Topographic maps: Illustrate Earth's surface shape.
- Road maps: Focus on transportation networks.
Projections in Mapping
- Different projection methods are employed to create flat representations of the Earth:
- Cylindrical Projection: Commonly the Mercator projection with straight latitude and longitude lines.
- Conic Projection: Maps shaped like a cone wrapping around a hemisphere.
- Azimuthal Projection: Touches the globe at a single point, often at a pole.
Latitude and Longitude
- Latitude: Imaginary lines running east-west, with examples including the Equator (0°) and poles (90°).
- Longitude: Imaginary lines running north-south, including the Prime Meridian (0°) and the International Date Line (180°).
Measurement of Time
- Sundial: Ancient timekeeping device using the sun's shadow.
- Water Clocks: Utilized the controlled flow of water to measure time.
- Hourglass: Measures time using sand.
- Standardized Time Zones: Earth divided into 24 time zones, each covering 15 degrees of longitude.
Rocks and Minerals
- Rocks are aggregates of one or more minerals, essential to Earth’s structure.
- The rock cycle is a continuous process involving the formation, transformation, and destruction of rocks.
Types of Rocks
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Igneous Rocks: Formed from solidified magma or lava.
- Intrusive: Slow cooling, large crystals (e.g., Granite).
- Extrusive: Rapid cooling, small/no crystals (e.g., Basalt).
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Sedimentary Rocks: Formed from accumulated sediment.
- Clastic: Composed of fragments of other rocks (e.g., Sandstone).
- Chemical: Formed from mineral precipitation (e.g., Limestone).
- Organic: Derived from biological sources (e.g., Coal).
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Metamorphic Rocks: Altered by heat, pressure, or fluids.
- Foliated: Layered appearance (e.g., Slate).
- Non-foliated: Lacks distinct layers (e.g., Marble).
Mineral Classification
- Eight main classes of minerals include:
- Native Elements: Pure elements (e.g., gold).
- Sulfides, Sulfates, Halides: Compounds often with metals (e.g., Pyrite, Gypsum).
- Oxides, Carbonates, Phosphates, Silicates: Various compositions forming essential minerals.
Physical Properties of Minerals
- Attributes such as color, streak, hardness (Mohs scale), and specific gravity help identify minerals.
- Luster describes how a mineral reflects light and can range from metallic to vitreous to greasy.
Importance of Rocks and Minerals
- Building blocks of Earth, contributing to soil health.
- Minerals have practical uses, including energy storage (Lithium) and medicinal applications (calcium carbonate).### Batteries and Materials
- Cobalt and nickel enhance the performance and stability of batteries; graphite serves as a conductor.
Geology and Rock Types
- Dating techniques determine the age of rocks, fossils, and geological events.
- Basalt is an igneous extrusive rock formed from rapidly cooled lava, used as aggregate in construction and for statues.
- Andesite, another extrusive rock, is typically found in lava flows and utilized similarly to basalt.
- Sandstone, formed from cemented sand grains, is a sedimentary rock used in concrete, glass, and paving.
- Limestone is composed of calcite and aragonite; it's essential for aggregate, cement production, and as a calcium source for animal feed.
- Coal, a sedimentary rock, results from plant material accumulation in swampy areas.
Environmental Importance of Rocks
- Porous rocks such as sandstone allow water passage, while clay minerals trap impurities.
- Mineral-rich soils bolster plant growth, sustaining entire food webs; caves and rocky shores provide habitats for animals.
Raw Materials and Construction Materials
- Minerals extracted from rocks serve as raw materials for products like cement and glass.
- Serpentine, a metamorphic rock, is known for its green waxy feel and is historically used for decorative purposes.
Economic Importance of Minerals
- Quartz is a prevalent mineral used in electronics, abrasives, and gemstones; its structure consists of oxygen and silicon.
- Clay minerals are foundational for ceramics, which are used to create various durable products.
Diastrophism and Earth’s Structure
- Diastrophism refers to the deformation of Earth's crust due to tectonic forces like compression, tension, and shearing.
- Orogenic processes involve mountain-building at convergent plate boundaries, exemplified by the Himalayas.
- Epeirogenic processes involve vertical movements caused by mantle convection, resulting in phenomena such as subsidence and uplift.
Theories of Diastrophism
- Plate tectonics describes the lithosphere's division into moving plates over the mantle.
- The Earth Expansion Theory posits that the Earth’s size has increased over time due to volcanic and continental drift activities.
- Contracting Earth Theory mentions that as Earth cooled from its molten state, it contracted, forming continents and ocean basins.
Stress and Strain
- Stress, the force applied to rocks, causes deformation, affecting their structure through various types, including compression, tension, and shear.
- Strain is the rock's response, leading to elastic (temporary) or plastic (permanent) changes in shape or breaking.
Earthquakes
- Earthquakes result in sudden ground shaking due to rock mass shifting below the surface.
- Seismic waves, the vibrations resulting from earthquakes, travel through the Earth and are measured to assess earthquake locations and energy release.
- Types of seismic waves include P-waves (fast and travel through all states of matter) and S-waves (slower, only through solids).
Volcanoes
- Volcanoes are openings in the Earth's crust where lava, ash, and gases escape, forming cone-shaped structures.
- Magma rises due to its lower density relative to surrounding rock; its eruption is influenced by gas content and viscosity.
Volcanic Eruption Types
- Effusive eruptions are non-explosive, while explosive eruptions are characterized by high gas content and viscosity.
- Signs of impending eruptions include increased volcanic activity, steam color changes, and drought-like symptoms in vegetation.
Safety Protocols during Volcanic Events
- Authorities provide updates and evacuation routes to enhance public safety before and during eruptions.
- After eruptions, cleanup requires masks to manage ash exposure.
Recent Volcanic Activities
- Mt. Kanlaon is noted as a significant volcanic site in the Philippines, contributing to the region’s geological dynamics.### Types of Lava
- Fluid Basaltic Lava: Can travel great distances due to its low viscosity.
- More Viscous Lavas: Travel shorter distances and form thicker lava flows.
- Pahoehoe Lava: Basaltic with a smooth, billowy, ropy surface, can cover extensive areas.
- Aa Lava: Sharp, splintery flows that are rubbly in texture.
- Blocky Lava: Characterized by larger blocks with angular edges resembling aa.
- Pillow Lava: Bulbous, spherical formations typically produced by underwater eruptions.
Volcanic Gases
- Primary volcanic gases include water vapor, carbon dioxide, and sulfur dioxide.
Impacts of Volcanic Eruptions
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On Humans:
- Property damage from lava flows can destroy homes and infrastructure.
- Health risks include burns and respiratory issues from inhaling ash.
- Ash can collapse roofs and disrupt transportation.
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On the Environment:
- Lava flows can lead to habitat destruction and loss of biodiversity.
- Ash can contaminate water sources, harming water quality and reducing air quality.
- Volcanic gases can contribute to air pollution and acid rain, adversely affecting crops and forests.
- Eruptions can influence climate by releasing greenhouse gases.
Types of Volcanoes
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Cinder Cones:
- Simplest and smallest volcanoes, composed of rock fragments.
- Rarely exceed 300 meters in height and have typical basaltic compositions.
- Eruptions are mostly explosive with minimal lava flow.
- Example: Taal Volcano.
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Composite Volcanoes (Stratovolcanoes):
- Large, with alternating layers of lava flows and pyroclastic deposits.
- Erupt periodically, exhibiting a range of magma compositions predominantly andesitic.
- Commonly found at subduction zones along the Pacific “Ring of Fire”.
- Example: Mayon Volcano.
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Shield Volcanoes:
- The largest volcanoes with broad, gentle slopes formed from fluid lava.
- Typically constructed from basalt and can span across large areas.
- Found at oceanic hot spots like the Hawaiian Islands.
- Produce vog (volcanic smog), a hazard to downwind populations.
- Example: Mauna Loa.
Volcanoes in the Philippines
- Active Volcanoes: Babuyan, Pinatubo, Mayon, Taal, Mt. Apo.
- Inactive Volcanoes: Dalupiri, Panuitan, Stayan, Sabtang, Mabudis.
Weathering Processes
- Hydration: Water absorption leads to mineral expansion (e.g., anhydrite to gypsum).
- Hydrolysis: Water-induced chemical reactions that alter resistant minerals (e.g., feldspar to kaolinite).
- Biological Weathering: Caused by living organisms, including plants and microorganisms.
Advantages and Disadvantages of Weathering
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Advantages:
- Formation of soil and shaping landscapes.
- Contribution to the rock cycle and carbon sequestration.
- Enhancements to agricultural productivity.
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Disadvantages:
- Can lead to natural hazards like landslides.
- Loss of natural beauty and infrastructure damage.
Soil Erosion and Control
- Soil Erosion: Geological process where earth materials are worn away and transported.
- Three key actions: detachment, transportation, and deposition.
- Soil Control Measures: Include building dikes, riprapping, contour plowing, terracing, crop rotation, reforestation, and establishing windbreaks.
Soil Formation Factors (CLORPT)
- Climate: Influences weathering rates based on temperature and moisture.
- Organisms: Plant and animal activity contributes to organic matter decomposition.
- Relief: Landscape features affect water retention and sunlight exposure.
- Parent Material: Originates from the underlying rock material.
- Time: Soil development is a gradual process, with older soils evolving distinct characteristics.
Types of Soil
- Sand Soil: Good drainage, low nutrients; acidic.
- Silt Soil: Retains moisture; fertile.
- Clay Soil: High water retention; sticky when wet.
- Loam Soil: Ideal for plant growth, a balanced mix of sand, silt, and clay.
- Chalky Soil: Alkaline, low in organic matter.
Soil Profile
- O Horizon: Organic layer rich in decomposed material.
- A Horizon: Most fertile topsoil, high in organic content.
- E Horizon: Leached layer with low minerals.
- B Horizon: Subsoil rich in leached minerals.
- C Horizon: Partially weathered material.
- R Horizon: Bedrock, unweathered rock beneath soil layers.
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Test your knowledge of geological concepts, including plate tectonics and fault types.
