Geological and Environmental Risks PDF

Geological and Environmental Risks that Generate Emergencies and Catastrophes Rodrigo Escribano Balín Geologist Geological l i l Engineer i  What is geology geology?? An academic d i definition...

Geological and Environmental Risks that Generate Emergencies and Catastrophes Rodrigo Escribano Balín Geologist Geological l i l Engineer i  What is geology geology?? An academic d i definition d fi i i off geology l could ld b be: Science that studies the history of the terrestrial globe, l b as wellll as the th nature, t f formation, ti evolution l ti and current disposition of the materials that compose itit. Earth science and aims to understand the evolution of the planet and its inhabitants, from the most ancient times to the present day through the analysis of rocks.  What is a rock? Solid materials, formed by crystals or grains of one or more minerals. On Earth, the crust is made up of rocks. View through a microscope of a 30 micron thin film  Classification of Rocks Rocks are classified into three main categories based on their formation: –Igneous Rocks –Sedimentaryy Rocks –Metamorphic Rocks  Igneous Rocks Formed from the cooling and solidification off magma or lava. l Classification based on Classification based on composition: texture: Felsic (e.g. (e g granite, granite rhyolite) Phaneritic (coarse‐grained, (coarse grained Intermediate (e.g. diorite, e.g. granite) andesite) Aphanitic (fine (fine‐grained grained, e.g. eg Mafic (e.g. gabbro, basalt) basalt) Ultramafic (e.g. (e g peridotite) Porphyritic (mixed grain sizes) Glassyy ((e.g. g obsidian)) What Are Igneous Rocks? https://youtu.be/PrN7jygu4cQ?si=UetXLnGKNVeoGpTE ps //you u be/ jygu cQ s Ue eo p  Sedimentary Rocks Formed from the deposition and consolidation of sediments sediments. Clastic sedimentaryy rocks: Chemical sedimentaryy rocks: Conglomerate Limestone Sandstone Dolomite Siltstone Rock salt Shale Gypsum Organic sedimentary rocks: Coal C l Some limestones Gas and oil  Metamorphic p Rocks Formed from the transformation of existing i i rocksk under d hi high h pressure and/or temperature temperature. Foliated metamorphic Non‐foliated metamorphic rocks: rocks: Slate Marble Phyllite Quartzite Schist Hornfels Gneiss Metamorphic Rocks https://youtu.be/oFOIWOoaK0s?si=kKxu5_2UM2RE4z6o  The Rocks Cycle A conceptual model that explains the relationships between these three rock types: Magma cools to form igneous rocks Weathering and erosion produce sediments Sediments are deposited and lithified to form sedimentary rocks k Any rock type can be metamorphosed under heat and pressure Melting of any rock type produces magma, restarting the cycle This overview provides a structured framework for understanding the main types of rocks and their formation processes. Geological time and its scale Carl Sagan ‐ Cosmos ‐ Cosmic Calendar https://youtu.be/Ln8UwPd1z20?si=qhiASHyO8_GvjeRT  Plate Tectonics Theory Plate Tectonics Theory is a fundamental concept in geology that explains how Earth's outer layer g , rigid is divided into large, g pieces p called tectonic plates. These plates move relative to each other, other driven by convection currents in the Earth's mantle Why do you think this can be useful to you in this master?  M t geological Most l i l disasters di t and d catastrophes occur in areas of union or distension of tectonic plates.  Earth's lithosphere p ((crust and uppermost pp mantle) is broken into several large and small p plates. These plates float on the partially molten asthenosphere. asthenosphere Plates move at rates of 2‐15 cm per year. Plate interactions occur at boundaries, which are classified as: – Divergent: plates move apart, creating new crust – Convergent: g p plates collide,, leadingg to subduction or mountain building – Transform: p plates slide ppast each other  Plate movements explain various geological phenomena including: phenomena, – Mountain formation – Earthquakes h k – Volcanic activity – Ocean basin formation EEvidence id supporting ti ththe th theory iincludes: l d Matchingg coastlines of continents Similar rock formations and fossils on different continents Patterns of earthquakes and volcanoes Magnetic striping on the ocean floor Pl t ttectonics Plate t i provides id a unifying if i fframeworkk ffor understanding Earth's geological processes and has revolutionized our understanding of Earth's y dynamic nature Plate Tectonics https://youtu.be/ryrXAGY1dmE?si=LoODHGM1tMI8QYdp ps //you u be/ y d s oO 8Q dp https://youtu.be/FbbwaAIMvvs?si=4RQZuhBlz6_keNp3 La Palama volcano (Canary Islands Islands)) 19th september 2021  Risks derived from geological processes Geological Hazards Seismic Hazards – Earthquakes – Tsunamis Volcanic Hazards – Lava flows – Pyroclastic flows – Ash falls – Lahars  Mass Movements – Landslides – Rockfalls – Debris flows Subsidence and Ground Collapse – Sinkholes – Land subsidence Flooding – River flooding – Flash floods  Geological Hazards Seismic Hazards –Earthquakes Earthquakes –Tsunamis  Earthquakes Definition and Cause An earthquake is a sudden shaking of the ground caused by the release of energy in the Earth'ss crust. Earth crust Most earthquakes occur due to the movement of tectonic plates along fault lines.  Earthquakes Measurement and Scale Earthquakes are measured using seismographs. The Richter scale (magnitude) and the Modified Mercalli scale (intensity) are commonly used to quantify earthquakes.  Seismographs Zhang Heng (78‐140 AD) Chinese Seismograph, Circa 132 AD Seismographs  Types of Seismic Waves P‐waves (Primary): Fastest, can travel through q solids and liquids S‐waves (Secondary): Slower, can only travel through solids Surface waves: Slowest, cause the most damage Earthquake Zones Most earthquakes occur along the "Ring of Fire" in the Pacific Ocean Fire Ocean. Other major zones include the Alpine‐ Himalayan belt and mid‐ocean ridges.  Effects and Hazards Ground shaking and rupture L d lid and Landslides d avalanches l h Tsunamis (in coastal areas) Liquefaction of soil Fires and infrastructure damage  Prediction and Preparedness Accurate prediction remains challenging Early warning systems can provide short‐term short term alerts Building B ildi codesd and d infrastructure i f design d i are crucial for mitigation Public education and emergency response plans are essential Antiseismic Architecture https://youtu.be/JyAoAOqJG6w?si=m9xB0v9AgWtxozFZ Seismic isolators Earthquakes 101 | National Geographic https://youtu.be/e7ho6z32yyo?si=QcCmiyVkDT8moVI9 htt // t b / https://youtu.be/_r_nFT2m‐Vg?si=Ht7ACw9uFU_xga6i FT2 V ? i Ht7AC 9 FU 6i Soil liquefaction due to earthquake. https://youtu.be/tW1iUAAMZZU?si=NeE1uZ4oVbotXeSw Earthquake frequency and building oscillation https://youtu.be/oeZ2M21XxhQ?si=AR96wgFvUca‐Go5y  TSUNAMI Definition and Cause A tsunami is a series of ocean waves caused by a sudden displacement of water. Most M commonly l triggered i dbby undersea d earthquakes, but can also be caused by landslides, volcanic eruptions, or meteorite impacts.  Wave Characteristics Tsunamis have extremely long wavelengths, often hundreds of kilometers. In deep ocean, tsunamis may be only a few centimeters high but travel at high speeds (up to 800 km/h). As they approach shore, tsunamis slow down and increase in height dramatically.  Impacts and Dangers Massive flooding of coastal areas Destruction of infrastructure and property Loss of life and displacement of populations Long‐term economic and environmental q consequences Japan Tsunami 2011 https://youtu.be/s5xpPzyVDx8?si=nji6V7opwJrdwDct  Volcanic Hazards Lava flows Pyroclastic flows Ash falls Lahars  Volcanism Definition and Formation A volcano is an opening in the Earth's Earth s crust through which magma, gases, and ash erupt. Formed at tectonic plate boundaries or over hot spots in the Earth's mantle.  Types of Volcanoes 1. Shield volcanoes: Broad, gently sloping 2. Stratovolcanoes: Steep, conical 3. Cinder cones: Small, steep‐sided 4. Caldera volcanoes: Large depressions formed by collapse  Eruption Types 1. Effusive: Characterized by lava flows 2 Explosive: 2. E l i Violent Vi l t ejection j ti off fragmented material 3. Mixed: Combination of both effusive and explosive activity  Volcanic Products 1. Lava flows 2 Pyroclastic materials (ash, 2. (ash pumice, pumice volcanic bombs) 3. Volcanic gases  Hazards to Humans Directt Hazards Di H d 1. Lava flows: Destroy everything in their path 2. Pyroclastic flows: Fast‐moving, extremely hot clouds of gas and debris 3 Lahars: 3. L h V Volcanic l i mudflows dfl that h can travell long l distances 4 Tephra 4. T h fall: f ll Ash A h and d llarger fragments f t that th t can collapse roofs and affect air quality 5 Volcanic gases: Can be toxic and cause 5. respiratory issues  Hazards to Humans IIndirect di H Hazardsd 1. Earthquakes: Often precede or accompany eruptions 2. Tsunamis: Can be triggered by underwater volcanic activity 3. Climate l effects: ff Large eruptions can cause temporary global cooling 4 Agricultural 4. A i lt l impacts: i t Ash A h can destroy d t crops and d contaminate water sources 5 Aviation hazards: 5. hazards Ash clouds can damage aircraft engines Mount Pinatubo Philippines (1991) L t day Last d off Pompeii P ii https://youtu.be/9lWtj2sjSHU?si=T1_owMdvoJ_OqTGQ Volcán Masaya y Por q qué NICARAGUA es "LA TIERRA DE LAGOS Y VOLCANES" https://youtu.be/sqPTmYPxnRY?si=w7jCb1BDIeeT2pQw  Mass Movements Landslides Rockfalls Debris flows A mass movement, or mass wasting, is the downslope movement of rock, soil, and debris under the influence of gravity. gravity It is a geomorphological process that occurs on both terrestrial and submarine slopes, and has been observed on other planetary bodies as well. Mass movements can happen gradually over long periods or suddenly suddenly, ranging from imperceptible creep to catastrophic landslides. 1. It is estimated that earth movements cause hundreds of thousands of deaths and injuries annuallyy around the world. 2. Slope movements are the third natural risk by number of victims after earthquakes and floods. 3. In Spain, although the figures are lower than in other mountainous countries, an average of 17 deaths are recorded annuallyy due to these phenomena.  Mass Movements One study mentions that around 2 disasters occur p per year y related to landslides, with an average of almost 200 victims annually. The most catastrophic event on record occurred in 1920 in China, causing approximately 100,000 deaths https://youtu.be/bTRdCvsl2ME?si=tWh2lx9oo_aTp9e3  Subsidence and Ground Collapse Sinkholes Land L d subsidence b id Ground Collapse is a sudden and often catastrophic downward movement or sinking of the Earth Earth'ss surface. surface It occurs when the ground loses its structural integrity and can no longer support the weight above it.  Subsidence and Ground Collapse This phenomenon can be caused by various g Natural processes factors, including: p such as the dissolution of underlying rock (in karst terrains) 1 Underground mining activities 1. 2. Excessive groundwater extraction 3. Subsurface erosion 4 Collapse 4. C ll off underground d d cavities iti or voids id  Subsidence and Ground Collapse Ground collapses can manifest in different forms, such as: Sinkholes: Circular depressions that form when the surface layer suddenly gives way Subsidence: A gradual settling or sinking of the Earth's surface Cave‐ins: Rapid and localized collapses often associated with underground structures  Flooding River flooding Flash Fl h floods fl d River floods and flooding occur when water levels rise above the top of river banks, causing water to overflow onto normallyll ddry lland. d  A river flood happens when water overflows the banks of a river channel and inundates surrounding areas that are usually dry. Common causes include heavy rainfall rainfall, rapid snowmelt, ice jams, dam failures, and tropical storms making ki landfall. l df ll Floodingg is a natural process p that helps p shape p landscapes, deposit nutrients, and support certain ecosystems adapted to periodic inundation. Camping de Biescas https://youtu.be/0mQ7XdYrbns?si=SrOEHBYwWbstTnm9 p //y /  Literature Cosmos (book). Carl Sagan, Ballantine Books ( (1980)) A Revolution in Earth Sciences: From Continental Drift to Plate Tectonics (book). (book) A. A Hallan, Oxford University Press (1975) Catastrophes (Earthwise Popular Science Books). S. Van Rose, British Geological Survey (2000)