Earthquakes

The epicenter of an earthquake is

• The point below the surface where rock begins to break and the first motion occurs

• The seismic station closest to the earthquake

• The place where the greatest damage occurs

• The point on the surface directly above the focus

Answer explanation

The epicenter of an earthquake is defined as the point on the surface directly above the focus, where seismic waves first reach the surface. This is why the correct answer is the point on the surface directly above the focus.

Tags

NGSS.MS-ESS3-2

Which travels fastest, always being the first detected by seismic stations?

• P waves

• S waves

Answer explanation

P waves, or primary waves, are the fastest seismic waves and are always the first to be detected by seismic stations. They travel through solids and liquids, making them the quickest to arrive after an earthquake.

Tags

NGSS.MS-PS4-1

An instrument that detects and measures earthquakes is a 

• seismogram

• focus seismic map

• focus

• seismograph 

Answer explanation

A seismograph is the correct instrument that detects and measures earthquakes. It records the motion of the ground during seismic events, unlike a seismogram, which is the output produced by a seismograph.

Tags

NGSS.MS-ESS3-2

Which of the following is NOT a cause of an earthquake?

• Collapse of Cavern

• Eruption of Volcano

• Lightning Strikes

• Moving Tectonic Plates

Answer explanation

Lightning strikes do not cause earthquakes. Earthquakes are primarily caused by the movement of tectonic plates, volcanic eruptions, and geological collapses, while lightning is an atmospheric phenomenon.

Tags

NGSS.MS-ESS3-2

What is a break in the lithosphere along which movement in an earthquake has first occurred?

• Earthquake

• Epicenter

• Fault

• Focus

Answer explanation

A fault is a break in the lithosphere where movement occurs during an earthquake. The focus is the point within the Earth where the earthquake originates, while the epicenter is the point directly above it on the surface.

Tags

NGSS.MS-ESS3-2

Where is the point at which the first movement occurs during an earthquake?

• Epicenter

• Focus

• Fault

• Plate

Answer explanation

The focus is the point within the Earth where the first movement occurs during an earthquake. The epicenter is directly above the focus on the surface, but the initial seismic activity starts at the focus.

Where is the point on the Earth’s surface directly above the focus of an earthquake?

• Epicenter

• Fault

• Hypocenter

• Tremor

Answer explanation

The epicenter is the point on the Earth's surface directly above the focus of an earthquake. It is where the seismic waves first reach the surface, making it the correct answer.

Which type of wave is the first to arrive after an earthquake occurs?

• P Wave

• Rayleigh Wave

• S Wave

• Shear Wave

Answer explanation

The first waves to arrive after an earthquake are P Waves (Primary Waves). They are compressional waves that travel fastest through the Earth, making them the first to be detected by seismographs.

Which body wave squeezes and stretches rock materials as they pass through the Earth?

• Body Waves

• P Waves

• S Waves

• Surface Waves

Answer explanation

P Waves, or primary waves, are body waves that compress and extend rock materials as they travel through the Earth. They are the fastest seismic waves and can move through both solids and liquids.

Which body waves cause move in a wave like pattern?

• Body Waves

• P Waves

• S Waves

• Surface Waves

Answer explanation

S Waves, or secondary waves, move in a wave-like pattern, causing particles to move perpendicular to the direction of wave travel. In contrast, P Waves compress and expand material, while Surface Waves travel along the surface.