Earthquakes and Plate Tectonics Review

Flashcards covering earthquake geology, plate tectonic theories, L'Aquila case study, and global natural disaster statistics.

Earthquake Prediction

It is not possible for scientists to accurately predict a specific earthquake by date and time (e.g., "there will be an earthquake on Wednesday at $11:52$ AM").

L'Aquila Scientists Appeal Result

The six scientists were acquitted of manslaughter, but the conviction of the public official was upheld by Italy's Supreme Court of Cassation in Rome.

Giampaolo Giuliani's prediction basis

Measurements of radon gas levels.

Giampaolo Giuliani's method status

It is not an accepted or proven method for earthquake prediction.

L'Aquila Earthquake Culture

Residents traditionally go outside and often sleep outside when the ground shakes.

Strike slip fault

A type of fault that is the result of shear stresses and occurs at transform plate boundaries.

April 6, 2009 L'Aquila Earthquake Magnitude

$$6.3$$

Mantle plume

A cylindrically shaped upwelling of hot mantle.

Indonesia

Geologically, it is a volcanic island arc.

Transform plate boundary

A boundary where two plates slide past each other, crust is cracked and broken but not created or destroyed, and volcanism is usually NOT associated.

Convergent-subduction zones

A plate boundary type associated with megathrust earthquakes, explosive volcanic eruptions, and tsunamis.

East African Rift Valley

A divergent (continental rift) plate boundary.

Convergent boundary

Occurs when two plates come together, causing edges to buckle into mountain ranges or one plate to bend into a seafloor trench; volcanoes often form parallel to the boundary.

Seafloor Spreading

Harry Hess' theory that explains how ocean crust is generated and destroyed.

Mid-ocean ridge rock age

Rocks close to mid-ocean ridges are younger than rocks far from mid-ocean ridges.

Layer of convection

The Mantle, where the convection necessary for plate motion occurs.

Ocean sediment thickness

Close to a mid-ocean ridge, sediment is less thick than the thickness far from mid-ocean ridges.

Normal polarity

A magnetic field that has the same polarity as the present magnetic field.

Oceanic-continental convergence

A type of convergence that results in a continental volcanic arc, such as the Andes Mountains.

Divergent boundary

Occurs when two tectonic plates move away from each other; magma rises to create new crust.

Continental Drift hypothesis rejection

The scientist could not provide a mechanism for the movement of the continents.

Plate Tectonics development

Geologists developed this theory in the $1960's$.

Pangaea

The supercontinent in the Continental Drift hypothesis.

Striations

Scratches or gouges cut into bedrock by glacial abrasion.

Alfred Wegener

The scientist who developed the Continental Drift hypothesis.

Natural disaster fatalities (past two decades)

$1,300,000$ people.

Floods

The most devastating natural disaster for urban residents (between $1980$ and $2009$) in terms of exposure, mortality, and economic losses.

Tropical cyclones

The second most devastating type of disaster for the world's cities in terms of disaster-related mortality.

Asiatic disaster statistics

The region that had the highest number of geophysical, hydrological, and meteorological disasters in the last three decades.

Coastal versus Inland city vulnerability

Coastal cities are more exposed to tropical cyclones, while inland cities are more vulnerable to droughts.

Japan

A country where four cities could expect to be hit by an earthquake with a magnitude of $8.0+$.

Low-income countries risk profile

Lowest proportion of cities with high exposure to natural disasters, yet the highest proportion of cities with high disaster-related mortality risk.

Mega-city vulnerability

Cities with populations over $10,000,000$ are the most likely to be located in high exposure areas and are most vulnerable.

Normal fault

A type of fault that results from tensional stresses and occurs at divergent plate boundaries.

Reverse fault

A type of fault that results from compressional stresses and occurs at convergent plate boundaries.

Piqiang Fault

A right-lateral strike slip fault.

Oblique-slip fault

A fault where ground shift occurs both laterally (e.g., $\sim 4.5\,m$) and vertically (e.g., bulged up by $\sim 1\,m$).