Topic 1 Flashcards
a specialized field within civil engineering focused on understanding, designing, and constructing structures and systems to withstand the forces and effects of earthquakes
earthquake engineering
Key Aspects of Earthquake Engineering
- Seismic Design
- Structural Analysis
- Seismic Codes and Standards
- Ground Motion Analysis
- Damage Assessment and Retrofit
- Risk Assessment and Management
Creating structures that can endure seismic forces
Seismic Design
Evaluating how structures respond to seismic activity through simulations and modeling to predict their behavior during an earthquake
Structural Analysis
Developing and implementing building codes and standards that dictate how structures should be designed and constructed to improve earthquake resilience
Seismic Codes and Standards
Studying how seismic waves travel through the ground and how they affect different types of soils and rocks
Ground Motion Analysis
Analyzing existing structures to assess their vulnerability to earthquakes and applying retrofitting techniques to improve their seismic performance
Damage Assessment and Retrofit
Evaluating the potential impact of earthquakes on communities and infrastructure, developing strategies to reduce risks and enhance preparedness
Risk Assessment and Management
Significance of Earthquake Engineering
- Ensuring safety and protecting lives
- Designing for dynamic loads
- Enhancing structural resilience
- Improving building codes and standards
- Integrating advanced technologies
- Addressing regional and site-specific risks
- Supporting post-earthquake recovery
- Educating and training engineers
- Contributing to sustainable development
- Promoting interdisciplinary collaboration
- Learning from past events
An oscillatory, sometimes violent movement of the Earth’s surface that follows a release of energy in the Earth’s crust
Earthquake
Elastic Rebound Theory was first proposed by _ following the _
Harry Fielding Reid, 1906 San Francisco earthquake
the theory that describes the process by which stress builds up in the Earth’s crust and is suddenly released, causing an earthquake
Elastic Rebound Theory
Key Concepts of Elastic Rebound Theory
- Stress Accumulation
- Elastic Deformation
- Rupture and Slip
- Seismic Waves
- Aftermath and Aftershocks
point on the Earth’s surface directly above the focus (also known as hypocenter)
epicenter
depth from the Earth’s surface to the focus
focal depth
is the shaking of the ground caused by sudden motions along faults, or fractures in the earth’s crust
earthquake
a fracture in the rocks that make up the earth’s crust
fault
the point at the surface of the earth directly above the focus
epicenter
the point within the earth where an earthquake rupture starts
focus/hypocenter
massive rocks that make up the outer layer of the earth’s surface, and whose movement along faults triggers earthquakes
tectonic plates
Distribution of Seismic Activity
- Tectonic Plate Boundaries
- Intraplate Earthquakes
- Seismic Zones
- Subduction Zones
where two plates collide
Convergent Boundaries
where two plates move apart from each other
Divergent Boundaries
where two plates slide past each other
Transform Boundaries
The most seismically active region in the world, surrounding the Pacific Ocean
Pacific Ring of Fire
A geological theory that explains the gradual movement of the Earth’s continents across the surface of the globe over geological time
Continental Drift
A geological theory that explains the gradual movement of the Earth’s continent across the surface of the globe over geological time
Continental Drift
Continental drift theory was first proposed by German meteorologist and geophysicist _ in _
Alfred Wegener, 1912
It laid the groundwork for the development of plate tectonics, which is now the widely accepted explanation for the movement of Earth’s lithosphere
Continental Drift
Plate tectonics move due to
mantle convection
slab pull
ridge push
explains not only the movement of continents but also the formation of mountains, earthquakes, and volcanic activity
Plate Tectonics
Continental drift is now understood as a component of the broader theory of plate tectonics
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revolutionized our understanding of Earth’s history and the dynamic nature of its surface
Continental drift
the scientific theory that explains the movement and interaction of the Earth’s lithosphere, which is divided into large, rigid plates
Plate Tectonics
rigid, outermost shell of the Earth
lithosphere
layer of rocks that forms the continents and the continental shelves
continental crust
layer of rocks that underlies the ocean basins
oceanic crust
lies directly beneath the lithosphere and is a semi-fluid, mechanically weak, and ductile layer of the upper mantle
asthenosphere
describes how the lithosphere floats at an equilibrium level on the asthenosphere, much like icebergs float on water
isostasy
describes how the lithosphere floats at an equilibrium level on the asthenosphere, much like icebergs float on water
isostasy
are large, rigid pieces of the Earth’s lithosphere that move and interact with each other on the planet’s surface
Tectonic plates
major tectonic plates include
Pacific Plate, North American Plate, Eurasian Plate, African Plate, South American Plate, Antarctic Plate, and Indo-Australian Plate
When two continental plates collide, neither is subducted due to their similar densities. Instead, the collision results in the crumpling and folding of the curst leading to the formation of mountain ranges
.
This movement occurs at mid-ocean ridges, where a new oceanic crust is created as magma rises from below the Earth’s surface
seafloor spreading
the sinking of a dense, subducted plate pulls the rest of the plate along with it, driving plate movement
slab pull
Formed from the cooling of magma at divergent boundaries or volcanic arcs
Igneous Rocks
The concept of plate tectonics developed in the 20th century, building on the earlier idea of continental drift proposed by Alfred Wegener
Igneous Rocks
The discovery of seafloor spreading, paleomagnetic evidence, and the global distribution of earthquakes and volcanoes provided strong support for the theory
.
largest tectonic plate covering much of the Pacific Ocean
Pacific Plate
surrounded by the “Ring of Fire,” a zone of high seismic and volcanic activity
Pacific Plate
The collision between the Indian portion of the Indo-Australian Plate and the Eurasian Plate has resulted in the uplift of the Himalayan mountain range
Eurasian, Indian
Name 6 minor tectonic plates
Nazca Plate, Cocos Plate, Caribbean Plate, Philippine Plate, Arabian Plate, Scotia Plate
The primary goals are to minimize damage, protect lives, and ensure that buildings and infrastructure remain functional during and after seismic events
Earthquake Engineering
Earthquakes with focal depths of less than approximately 60 km are classified as
Shallow Earthquakes
have focal depths ranging from 60 to 300 kilometers
Intermediate Earthquakes
Classification of Earthquakes in terms of focal depth
Shallow Earthquakes, Intermediate Earthquakes, Deep Earthquakes
List Evidence for Continental Drift
Examples are (1) fit of the continents (2) fossil evidence (3) geological evidence (4) paleoclimactic evidence
Wegener noted that the coastlines of continents like South America and Africa fit together like pieces in a jigsaw puzzle, suggesting they were once joined
Fit of the Continents
Identical fossils of plants and animals, such as the Mesosaurus (a freshwater reptile), were found on continents now separated by vast oceans, indicating these continents were once connected.
Fossil Evidence
Initially, Wegener’s theory was met with skepticism because he could not provide a convincing mechanism for
how continents could move through solid oceanic crust.
