The first primary earthquake hazard, surface rupture, can be caused by vertical or horizontal displacement on either side of a ruptured fault, which can affect enormous areas of land (tectonic movement).
What happens to the surface of the Earth during an earthquake?
An earthquake can push and pull the ground, tearing the surface and pushing the ground apart and upward. These are known as “surface ruptures.” A surface rupture may occur suddenly during an earthquake, or it can happen more slowly—in either case, surface ruptures often happen along preexisting faults.
What is surface rupture of an earthquake?
Surface rupture occurs when movement on a fault deep within the earth breaks through to the surface. NOT ALL earthquakes result in surface rupture. What is an earthquake and what causes them to happen? An earthquake is caused by a sudden slip on a fault.
What is it called when an earthquake occurs suddenly?
Surface Rupture. These are known as “surface ruptures.” A surface rupture may occur suddenly during an earthquake, or it can happen more slowly—in either case, surface ruptures often happen along preexisting faults . During the 1992 Landers earthquake in San Bernardino County, a surface rupture extended for some 50 miles.
What causes an earthquake?
An earthquake is caused by a sudden slip on a fault. The tectonic plates are always slowly moving, but they get stuck at their edges due to friction.
What is an aftershock?
What is surface rupture?
Why do earthquakes happen?
Where do aftershocks occur?
Which fault pushed frozen sand and gravel over the snow surface?
How deep does an earthquake occur?
What causes earthquakes?
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What causes a fault to rupture?
Surface rupture occurs when movement on a fault deep within the earth breaks through to the surface.
Does ground shaking cause ground rupture?
Ground rupture is another important effect of earthquakes which occurs when the earthquake movement along a fault actually breaks the Earth's surface.
What is the common manifestation of ground rupture?
Disruptive up, down and sideways vibration of the ground during an earthquake. Phenomenon wherein sediments, especially near bodies of water, behave like liquid similar to a quick sand. Down slope movement of rocks, soil and other debris commonly triggered by strong shaking.
Why is ground rupture a hazard?
When the focus of the earthquake is shallow, a fault rupture may break through to the Earth's surface, deforming the ground and producing deep ruts, steep banks and lateral displacements. These ground deformations can cause severe damage to structures, roads, railways and buried infrastructure, such as pipelines.
What is the difference between ground shaking and ground rupture?
Ground Rupture - Deformation on the ground that marks the intersection of the with the earth's surface. Effects: Fissuring, displacement of the ground due to movement of the fault. 2. Ground Shaking - Disruptive up, down and sideways vibration of the ground during an earthquake.
Can ground rupture be prevented?
We cannot prevent natural earthquakes from occurring but we can significantly mitigate their effects by identifying hazards, building safer structures, and providing education on earthquake safety. By preparing for natural earthquakes we can also reduce the risk from human induced earthquakes.
What should I do before ground rupture?
Secure heavy furniture, hanging plants, heavy pictures or mirrors. Keep flammable or hazardous liquids in cabinets or on lower shelves. Maintain emergency food, water and other supplies, including a flashlight, a portable battery-operated radio, extra batteries, medicines, first aid kit and clothing.
Which factor affects the characteristic of ground rupture?
Factors affecting the characteristics of ground ruptures These factors include the type of fault movement (reverse, normal, or strike-slip) and the inclination of the fault plane.
What causes the ground to split?
Soil cracks when it has a large amount of clay and it is exposed to hot, dry conditions. Clay sticks together when the soil is wet, but as it dries out, the clay shrinks and causes cracks that are nearly impossible for roots to penetrate.
Is ground rupture a primary hazard?
The effects of earthquakes can be broadly grouped into two categories – primary and secondary hazards. Primary hazards are caused by the direct interaction of seismic wave energy with the ground. In most situations, this is limited to fault rupture and ground shaking.
How can the impacts of ground rupture be mitigated?
When avoidance is not possible, geotechnical mitigation strategies can be used. These strategies include spreading fault displacement over a large area, causing the structure to respond with rigid-body movement, and diverting the fault rupture around the structure.
Is ground rupture primary or secondary?
Primary hazards include ground shaking, landslides (a downward sliding of a dry mass of the earth either from mountains or cliffs), liquefaction (when the soil is reduced to a liquid) and surface rupture (breaking of the surface along a fault).
What happens when the ground is shaking?
Ground shaking is a term used to describe the vibration of the ground during an earthquake. Ground shaking is caused by body waves and surface waves. As a generalization, the severity of ground shaking increases as magnitude increases and decreases as distance from the causative fault increases.
What will happen if there is ground shaking?
Any buildings in the path of these surface waves can lean or tip over from all the movement. The ground shaking may also cause landslides, mudslides, and avalanches on steeper hills or mountains, all of which can damage buildings and hurt people.
What happens when the ground shakes?
When the plates hit a roadblock, stress builds and leads to cracks in the Earth called faults. In time, the energy from within builds to the breaking point. That sudden release leads to an earthquake. The shaking begins at a central region called the epicenter and spreads far and wide.
Does ground shaking due to earthquake trigger landslide?
Earthquakes often trigger landslides, causing significant and even catastrophic damage to houses.
Earthquake Surface Rupture: A Brief Survey on Interdisciplinary ...
Coseismic surface ruptures during desctructive earthquakes (1999 Kocaeli–Düzce, Turkey and 1999 Chi-Chi, Taiwan) have caused devastating effects on buildings and infrastructures. Surface rupture remains a complicated phenomenon involving variable movements along near surface traces of both primary and secondary faults. The surface rupture patterns observed in nature, the rupture zone width ...
Surface rupture - Wikipedia
In seismology, surface rupture (or ground rupture, or ground displacement) is the visible offset of the ground surface when an earthquake rupture along a fault affects the Earth's surface. Surface rupture is opposed by buried rupture, where there is no displacement at ground level.This is a major risk to any structure that is built across a fault zone that may be active, in addition to any ...
Surface rupture » Seismic Resilience
Surface rupture. The first primary earthquake hazard, surface rupture, can be caused by vertical or horizontal displacement on either side of a ruptured fault, which can affect enormous areas of land (tectonic movement).
What is surface faulting?
Ground Rupture & Surface Faulting From Earthquakes. An earthquake can push and pull the ground, tearing the surface and pushing the ground apart and upward. These are known as “surface ruptures.”. A surface rupture may occur suddenly during an earthquake, or it can happen more slowly—in either case, surface ruptures often happen along preexisting ...
How far did the 1992 Landers earthquake extend?
During the 1992 Landers earthquake in San Bernardino County, a surface rupture extended for some 50 miles. If a surface rupture develops close to or at your house location, it can cause considerable damage to structures as well as to land.
What is CEA insurance?
CEA earthquake-insurance policies provide coverages for rebuilding and repair, loss of use, and personal property, even breakables. Contact your insurance agent or residential insurance company to find the CEA policy right for you.
Can you retrofit a house to withstand a surface rupture?
For that reason, it may be financially prohibitive. The Earthquake Brace + Bolt program maintains a searchable database of California engineers.
What is a geotechnical engineer?
A geotechnical or civil engineer can advise or help with retrofit plans to reduce risk to your house from earthquake-induced landslides. The Earthquake Brace + Bolt program maintains a searchable database of California engineers.
How many landslides did the 1994 earthquake cause?
Earthquake-Induced Landslides. In January 1994, the magnitude 6.7 Northridge earthquake triggered over 11,000 landslides, contributing to the quake's total $20 billion in property damage centered around the San Fernando Valley region. Earthquakes often trigger landslides, causing significant and even catastrophic damage to houses.
What is retrofitting a house?
Retrofitting for a geologic hazard often involves both structural foundation changes like bracing and bolting, and changes to the property surrounding the house. This can be time-consuming and costly.
What happens if a house is in the path of an earthquake?
If your house is in the path of an earthquake-induced landslide, it is at risk for damage from landslide debris, as well as sliding downhill itself. MyHazards can help you find out if the area where you live or work is prone to earthquake-induced landslides.
1. Surface Rupture
It is the actual displacement and cracking of the ground surface along a fault trace. Surface rupture is confined to a narrow zone along an active fault. Rupture may happen rapidly during an earthquake or it may not occur at all. Displacement beneath a building that exceeds 1 or 2 inches can have a catastrophic effect.
2. Ground Shaking
It is the actual trembling or jerking motion produced by an earthquake. It causes widespread damage is one of the most difficult seismic effects to quantity and predict. The damage varies with wave length, duration of shaking, nature of underlying materials, and character of structures.
3. Ground Failure
This is because of ground acceleration from an earthquake produces landslides, ground cracking, subsidence and differential settlement. Hilly slopes can fail under a dynamic load, the stress from earthquake motion. Liquefaction is another mechanism of ground failure during an earthquake.
4. Tsunamis and Seiches
These are similar effects that occur in bodies of water. Tsunami is a Japanese term for large ocean waves generated by submarine earthquakes. Rapid displacement of an undersea fault can cause a wave travelling thousands of miles from the epicenter. On the deep ocean, the tsunami height typically is 1 ft.
What is CEA earthquake insurance?
CEA earthquake-insurance policies provide coverages for rebuilding and repair, loss of use, and personal property, even breakables. To learn more about CEA earthquake policy coverages, please take advantage of our free Training courses. Also, learn more about helping your customer understand the value of a CEA policy.
What happens if a surface rupture develops close to or at the homeowner's house location?
If a surface rupture develops close to or at the homeowner's house location, it can cause considerable damage to structures as well as to land.
What are earthquake fault zones?
Earthquake fault zones designated by CGS are delin- eated on a separate series of maps. CGS geologists place earthquake fault zones along traces of faults where mapping demonstrates surface fault rupture has occurred within the past 11,000 years (Holocene time). Construction within these zones cannot be permitted until a geologic investigation has been conducted to prove that a building planned for human occupancy will not be constructed across an active fault. These types of site evaluations address the precise location and recency of rupture along traces of the faults and typically are based on observations made in trenches excavated across fault traces. As of April 2006, CGS has released 547 official maps statewide.
What is the term for the loss of strength of saturated soils during shaking?
Liquefaction —as a geologic term, refers to the loss of strength of saturated soils during shaking. An earthquake can cause soil particles to shift and become buoyant, as pore spaces filled with water, which weakens the ability of a soil to support structures on the surface.
What is surface rupture?
EARTHQUAKE-INDUCED GROUND FAILURE HAZARDS. Surface rupture—occurs when movement on a fault deep within the earth breaks through to the surface. Fault rupture almost always follows pre-existing faults, which are zones of weakness. Rupture may occur suddenly during an earthquake or slowly in the form of fault creep.
How are slopes weakened?
Slopes are weakened by weathering, erosion, saturation, and the addition of weight in the form of artificial fill, structures, snow, or rock . Landslides that occur during earthquakes typically originate from these steep and weakened slopes.
What is the code for landslide mitigation?
Areas where previous occurrence of landslide movement, or local topographic, geological, geotechnical and sub- surface water conditions indicate a potential for permanent ground displacements such that mitigation as defined in Public Resources Code Section 2693(c) would be required.
Do real estate sellers have to check seismic zones?
In all cases, real property sellers are required to check seismic zonation maps produced by CGS to determine whether property being sold falls within a seismic hazard zone. The seller is required to provide a “Natural Hazard Disclosure Statement” to the buyer.
What is an aftershock?
"Foreshock" and "aftershock" are relative terms. Foreshocks are earthquakes that precede larger earthquakes in the same location. An earthquake cannot be identified as a foreshock until after a larger earthquake in the same area occurs. Aftershocks are smaller earthquakes that occur in the same general area during the days to years following a...
What is surface rupture?
Surface rupture occurs when movement on a fault deep within the earth breaks through to the surface. NOT ALL earthquakes result in surface rupture.
Why do earthquakes happen?
An earthquake is caused by a sudden slip on a fault . The tectonic plates are always slowly moving, but they get stuck at their edges due to friction. When the stress on the edge overcomes the friction, there is an earthquake that releases energy in waves that travel through the earth's crust and cause the shaking that we feel. In California there...
Where do aftershocks occur?
Aftershocks occur near the fault zone where the mainshock rupture occurred and are part of the "readjustment process” after the main slip on the fault. Aftershocks become less frequent with time, although they can continue for days, weeks, months, or even...
Which fault pushed frozen sand and gravel over the snow surface?
Near the southeast extent of the surface rupture of the Totschunda fault thrust faulting pushed the frozen sand and gravel over the snow surface.
How deep does an earthquake occur?
Earthquakes occur in the crust or upper mantle , which ranges from the earth's surface to about 800 kilometers deep (about 500 miles). The strength of shaking from an earthquake diminishes with increasing distance from the earthquake's source, so the strength of shaking at the surface from an earthquake that occurs at 500km deep is considerably...
What causes earthquakes?
Earthquakes can be induced by a wide range of causes including impoundment of reservoirs, surface and underground mining, withdrawal of fluids and gas from the subsurface, and injection of fluids into...