Plate Tectonics and Volcanoes

Plate Tectonics

• Divergent Movement (Constructive): Magma pushes plates apart, forming new crust as it surfaces
• Convergent Movement (Destructive): Oceanic plate slides under continental plate, crust is lost and trenches/volcanoes are made as plates collide
• Transform Movement (Conservative): Plates slide horizontally past each other creating earthquakes, with no crust created or destroyed

Types of Volcanoes

• Shield Volcano: Largest on Earth, forms outside plate boundary, lava has low viscosity
• Shield Volcano Example: Mauna Loa, Hawaii
• Composite Volcano: Tall with many ash layers, powerful explosives with sudden explosions of ash and toxic gases
• Composite Volcano Example: Mount Fuji
• Cinder Volcano: Few in number, ~100 feet tall, often near bigger volcanoes, explosive bursts of small solid lava fragments
• Cinder Volcano Example: Wizard Island, Crater Lake National Park
• Super Volcano: Different shapes, large calderas (large divots in ground), erupts magma causing caldera to form, large magma explosions
• Super Volcano Example: Yellowstone National Park

Earthquakes

• Results from movements around fractures in rocks, known as a fault
• Stress accumulates and releases suddenly
• Focus (hypocenter): Point of break
• Epicenter: Area of surface land above the focus

Waves

• Seismic: Travel in all directions from the epicenter, faster through hard rock, slower through loose sediment/water
• P and S waves: Travel through earth itself, less destructive than surface waves
• P waves: Moves back and forth, going through solid, liquid, and gas (body waves)
• S waves: Moves up and down (solids only); secondary waves
• Love waves: Move in all directions faster
• Rayleigh waves: Move like ocean waves in long duration

Shaking

• Magnitude: energy released, depending on plate thickness
• Shaking decays with distance
• Local soil can amplify shaking

Faults

• Strike-slip: Moves horizontally in opposite directions; for example, San Andreas Fault
• Normal: Tension, stresses rocks apart, basin range, hanging wall moves down footwall
• Reverse: Hanging wall moves up footwall, compression stresses rocks together; for example, Saint Gabriel Faults
• Surface fault: Displacement that reaches the earth’s surface during a slip

Secondary Hazards

• Liquefaction: Water-saturated sediment temporarily loses strength, acts as a fluid. Caused by earthquake shaking, loses ability to support structures
• Landslide: Movement of surface material down a slope
• Tsunami: Large series of waves, large wavelength, initially high rising water levels, lasts minutes/hours

Mass Movements

• Influenced by gradient of slope, water (more water = more movement) and Vegetation (roots bind soil, deforestation increases movements)
• Influenced by Human Activity like construction, transportation lines, etc

Types of Movement

• Landslide: Caused by human activity due to loosened soil becoming unstable and human construction
• Mudflow: Landslide-like, sustained rainfall, volcanic activity, very fast due to low rainy watery viscosity, some reach 60 mph
• Rockfall: Vulnerable locations that don't receive lots of rainfall typically
• Soil Creep: Terracettes in the soil, ridges, trees with bent trunks or curved, houses from cracks, ground is generally unstable

Vulnerability

• According to the world risk report 2012: the level of risk in any given country depends on the economic, social and institutional conditions of its society
• Hazards are costing more damage, but fewer lives are lost
• Long term California earthquake rates suggest a 2 in 3 chance will strike the San Francisco Bay area in 30 years
• 80% of US population resides in urban areas
• Elderly and children are more vulnerable
• Women are more vulnerable due to their role in society
• Less developed areas are more vulnerable

Projects

• Mass Movements in California (January 2018) and Wayanad, India (July 2024)
• Volcanic Hazard in Volcán de Fuego, Guatemala (June 2018) and Mount Ontake, Japan (September 2014)
• Earthquake Hazard in Tohoku, Japan (March 11, 2011) and Southern Türkiye & Northern Syria (February 6, 2023)

2010 Eyjafjallajokull, Iceland Volcano Eruption

• Rural/urban: Rural, underneath glacier; earthquakes in January caused subduction
• Degree of isolation: Very rural area, no deaths due to lack of homes; all evacuated
• Levels of development: Immediate halt to air traffic
• Lava caused ice to melt, flooding and mudslides destroying crops, severely hurting Iceland's agricultural sector
• Population density: ~800 people near Austur-Eyjafjöll (104) and Vík (311) evacuated
• Hazard Magnitude/Frequency: 3-4 on VEI; occurred three times in recorded history (920, 1610, and 2010)
• Secondary hazards: flooding and minor mudslides into agricultural lands, closing airports and causing air quality hazards

2010 Eruption Management

• Pre-event strategies: building codes, emergency drills, early warning systems, hazard monitoring etc
• Post-event strategies: Iceland triggered the creation of the International Volcanic Ash Task Force to identify atmospheric risk on aircrafts
• Produced a fountain-fed lava flow field of about 1.3 km2
• Flight cancellations: Over 100,000 flights were canceled, affecting 10 million passengers
• Impact: No casualties (everyone evacuated); most damage from ash in area
• Impact: Air quality significantly decreased
• Impact: The airline industry lost $200 million a day as air travel was cancelled;
• The European Red Cross provided food; Economy expanded by 10%; Icelandic government implemented evacuation plans
• Tourism decreased 17.5% then increased back post-eruption
• Initiating event: Earthquakes in January caused subduction under glacier
• Typically erupts simultaneously with Katla, Iceland, but on March 10, erupted alone then lava started to flow down Fimmvorduhals Pass separating two glaciers which led to melting
• More eruptions and steam to occur as the ice vaporized

Indonesia Volcano & Tsunami: Anak Krakatau

• December 2018, Anak Krakatau, Indonesia
• The presence of a flank collapse led to a tsunami reaching South Asia, East Africa, and Western Australia
• Zero population on the island of Anak Krakatau
• Seismic Magnitude - between 4.8 and 5.9
• 22 December 2018 Sunda Strait tsunami due to volcanic flank failure, a sector collapse
• Underwater landslide displaced large amounts of water creating waves without warning; seismic activity did not trigger alerts
• Possibilities: building codes, emergency drills, early warning systems, hazard monitoring, etc
• Prior to this tsunami, the government of Indonesia released a status of the activities of Mount Anak Krakatau since June 2018
• Warning system only detects earthquake-generated tsunamis; locals received no warning
• InSAR maps showed southern side of volcano slipped towards ocean at 4 millimeters/month; flank movement increased to 10 millimeters/month as eruptive activity increased in June
• Not enough of a concern
• Statistics: Mount Anak Krakatau erupts 40x over past 85 years, 130 volcano-induced tsunamis over past 4 centuries
• Impact: At least 36,417 deaths, people suffered loss of hearing in close vicinity
• The volcanic ash led to deteriorating health conditions and the destruction of 165 villages and towns

Future Resilience and Adaptation

• Hazard Communication: Mobile device containing child's images, location
• Seperated parents and children in database for family tracing can help quickly collect, sort, and share
• Separated children are vulnerable
• Process minimizes separation time
• Mass numbers of people helped in a timely manner
• Reduces the long term physiological and traumatic effects of being missing with data that can be used in future crises
• Urbanization and the increasing global middle class causes increased losses from natural disasters
• This can be mitigated with insurance, improved infrastructure, and preparedness

Hazard Response

• 90% of disaster deaths between 1996 and 2015 occurred in low and middle-income nations
• Turkey and Syria earthquake damaged the only official humanitarian aid route
• Wealthier nations upgrade old buildings, build better infrastructure, and invest in resources
• January 2010: Haiti earthquake killed an estimated 220,000, injured 300,000, and left 1.5 million homeless
• Chile earthquake at 8.8 magnitude had 500 deaths and slightly structural damage
• California has earthquake insurance policies dropped by 5.5% last year
• Only about 10-15% of homeowners have earthquake insurance translating to 1,615,561 policies in 2023

Japan Earthquake and Tsunami

• The Fukushima Daiichi nuclear disaster occurred due to flooding of backup generators highlighting vulnerabilities in infrastructure and tsunami wiped out entire towns
• Resulted from thrust faulting on the subduction zone plate boundary between the Pacific and North America plates
• Maximum wave height of almost 40 meters (130 feet)
• A 1,242-mile) stretch of Japan's Pacific coast was impacted by the tsunami
• Biggest catastrophic event was the nuclear disaster from the Tsunami as disabled the power supply and cooling of 3 Fukushima Daiichi reactors
• Damages were around $220 Billion USD (most expensive natural disaster in history_

2023 Southern Turkiye & Northern Syria Earthquakes

• The earthquake affected 15.73 million people across Türkiye and Syria and 230,000 buildings were damaged or destroyed in Türkiye with 10,600 in northwest Syria
• Magnitude: 7.8, followed by a 7.5 quake nine hours later with thousands of aftershocks and additional tremors
• Government allocated substantial funds for earthquake relief amounting to 3.6% of GDP in 2023 and 2.4% in 2024; had National Earthquake Strategy and Action Plan
• Casualties over 55,000 deaths with economic losses exceeding $100 billion
• There was a lack of military rescue forces and thousands of landslides occurred impacting the water supply with the Turkish government blocking twitter to stop criticism
• Strengthened compliance with seismic safety standards and improving emergency coordination