earthquakes week 1

Seismic Waves

Vibrations that travel through the Earth, typically caused by earthquakes or explosions.

P Waves (Primary Waves)

Seismic waves that result in back-and-forth motion of the ground in the direction of wave propagation and travel faster than S or surface waves.

S Waves (Secondary Waves)

Seismic waves that cause motion of the ground perpendicular to the direction of wave propagation, slower than P waves.

Surface Waves

Seismic waves that travel along the Earth's surface and are slower than both P and S waves.

Rayleigh Waves

A type of surface wave that results in a rolling motion of the ground, similar to waves on a beach.

Love Waves

A type of surface wave causing back-and-forth ground motion perpendicular to wave propagation, confined to the Earth's surface.

Travel Time Curve

A graph that shows the relationship between distance from the earthquake source and the time taken for seismic waves to arrive.

Mohorovičić Discontinuity

The boundary between the Earth's crust and mantle, recognized through seismic P waves.

Outer Core

The fluid layer of the Earth's core that generates the Earth's magnetic field.

Inner Core

The solid innermost layer of the Earth, believed to be primarily composed of iron and nickel.

Continental Drift

The hypothesis that continents were once connected and have drifted apart over geological time.

Plate Tectonics

The scientific theory explaining the movement of Earth's lithosphere which is broken into tectonic plates.

Sea-Floor Spreading

The process by which new oceanic crust forms as magma rises to the ocean floor at mid-ocean ridges.

Lithosphere

The outer layer of the Earth made up of the crust and the upper mantle, characterized by its rigidity.

Asthenosphere

The semi-fluid layer beneath the lithosphere that allows for tectonic plate movement.

Geophysical Measurements

Observations and data collected to understand Earth's internal structure and tectonic processes.

Tectonic Plates

Massive pieces of the Earth's lithosphere that move and interact at their boundaries, causing geological activity.

Seismic Tomography

A technique that uses seismic waves to create 3D images of the Earth's interior structure.

Global Seismicity

The distribution of earthquakes across the globe, indicating active tectonic processes.

Curie Temperature

The temperature at which certain materials lose their permanent magnetic properties, around 500°C for basalt.