Table of Contents
- 1 What is the focus of an epicenter?
- 2 What are P and S waves?
- 3 Where do most earthquakes happen?
- 4 Why is it important to determine the epicenter?
- 5 What is Hypocentral depth?
- 6 What is an earthquake’s epicenter?
- 7 How does a seismograph work?
- 8 What is a locked fault?
- 9 What is the meaning of S waves?
- 10 What frequency do earthquakes shake at?
What is the focus of an epicenter?
Epicenter-The point on the Earth's surface located directly above the focus of an earthquake. Focus-The location where the earthquake begins. The ground ruptures at this spot, then seismic waves radiate outward in all directions.
What are P and S waves?
Our transcription: Geologists divide the seismic waves that travel through the Earth's interior into two basic types, "primary" or "P-waves" and "secondary" or "S-waves." A P-wave is a compressional wave that makes the rock vibrate parallel to the direction of its movement.
Where do most earthquakes happen?
Most earthquakes occur along the edge of the oceanic and continental plates. The earth's crust (the outer layer of the planet) is made up of several pieces, called plates. The plates under the oceans are called oceanic plates and the rest are continental plates.
Why is it important to determine the epicenter?
The main importance in determining the epicentre is so that the fault that ruptured causing the earthquake can be identified. If the fault is a recognised fault, then the earthquake can be used to increase confidence in the hazard modelling for the area.
What is Hypocentral depth?
An earthquake's hypocenter is the position where the strain energy stored in the rock is first released, marking the point where the fault begins to rupture. This occurs directly beneath the epicenter, at a distance known as the focal or hypocentral depth.
What is an earthquake’s epicenter?
epicenter. The epicenter is the point on the earth's surface vertically above the hypocenter (or focus), point in the crust where a seismic rupture begins.
How does a seismograph work?
A seismograph is a device for measuring the movement of the earth, and consists of a ground- motion detection sensor, called a seismometer, coupled with a recording system. … As the earth moves, the relative motion between the weight and the earth provides a measure of the vertical ground motion.
What is a locked fault?
A locked fault is a fault that is not slipping because frictional resistance on the fault is greater than the shear stress across the fault (it is stuck). Such faults may store strain for extended periods that is eventually released in an earthquake when frictional resistance is overcome.
What is the meaning of S waves?
S-wave. noun. The definition of an S wave, or secondary wave, is a wave motion in a solid medium where the medium moves perpendicular to the direction of the travel of the wave. An example of an S wave is when pieces of rock in an earthquake vibrate at right angles to the direction of the seismic wave.
What frequency do earthquakes shake at?
Most earthquake waves have a frequency of less than 20 Hz, so the waves themselves are usually not heard. Most of the rumbling noise heard during an earthquake is the building and its contents moving. When the Chilean earthquake occurred in 1960, seismographs recorded seismic waves that traveled all around the Earth.