Earthquake Intensity and Geology Concepts

Flashcards covering essential concepts from geology and earthquake intensity.

What does Modified Mercalli Intensity (MMI) measure?

The observed shaking and damage an earthquake causes to people, structures, and the environment.

What does Moment Magnitude (Mw) measure?

The total energy released during an earthquake based on fault rupture area and slip amount.

What is an ore?

A rock containing a high enough concentration of a valuable metal to be extracted profitably.

What are critical minerals?

Minerals essential for national security or the economy whose supply chain is at risk.

What is lithification?

The process that transforms loose sediment into solid sedimentary rock.

What are the four categories of sedimentary rocks?

Clastic, Chemical, Organic, Biochemical.

How do rock color, grain size, grain shape, sorting, and composition help determine depositional environment?

These features reveal energy level, oxygen availability, and transport distance.

What does the organization of shoreline → shelf → deep marine deposits look like?

Near shoreline: sandstone; Shelf: siltstone/shale; Deep marine: limestone or chert.

What defines physical (mechanical) weathering?

The breakdown of rock into smaller fragments without changing its chemical composition.

What defines chemical weathering?

The chemical alteration of minerals, producing new minerals and ions in solution.

What is soil?

Disaggregated and chemically altered rock material mixed with organic matter, typically arranged in horizons.

What are the soil horizons from top to bottom?

O → A → E → B → C.

What are the four soil-forming processes?

Additions, Transformations, Translocations, Removals.

What is mass wasting?

The downslope movement of rock, sediment, or soil due to gravity.

How does water influence landslides?

It adds weight (driving stress) and reduces friction, making slopes more likely to fail.

What are the three main causes (drivers) of metamorphism?

Heat, pressure, and chemically active fluids.

What is metamorphic grade?

The intensity of metamorphism — based on temperature and pressure conditions.

What is foliation?

The layered/aligned texture formed when platy minerals align under directed pressure.

What is stress in geology?

Force applied over an area — the cause of deformation.

What are the three types of differential stress?

Compression, Tension, Shear.

What is a fault?

A fracture in rock where significant movement has occurred.

What is a fold?

A bend or warp in rock layers caused by plastic deformation under compression.

What does the geologic (long-term) carbon cycle describe?

The slow exchange of carbon between the atmosphere, lithosphere, and mantle over millions of years.

What is residence time?

The average amount of time a carbon atom stays in a reservoir.