Table of Contents
What are the types of ground motion?
Four types of ground motions are considered, i.e. (1) one at rock site in near-fault earthquake (near-fault rock motion), (2) one at soil site in near-fault earthquake (near-fault soil motion), (3) one of long-duration at rock site (long-duration rock motion) and (4) one of long-duration at soil site (long-duration …
How do earthquakes make the ground move?
The energy radiates outward from the fault in all directions in the form of seismic waves like ripples on a pond. The seismic waves shake the earth as they move through it, and when the waves reach the earth’s surface, they shake the ground and anything on it, like our houses and us!
Can you see the ground move during an earthquake?
The physical wave being viewed may be manifested by movement of grass tops or dust particles, as “road-mirage” type changes, or as true wave motion in soil, but because of the stroboscopic effect even high-speed surface seismic waves traveling at speeds of kilometers per second could become visible as slow-speed …
What are the characteristics of a strong earthquake ground motion?
To explain this phenomenon in terms of ground motion characteristics, based on 58 sets of strong ground motions in this earthquake, the peak ground acceleration (PGA), peak ground velocity (PGV), acceleration response spectra (Sa), duration, and Arias intensity are analyzed.
Can the ground open up during an earthquake?
Shallow crevasses can form during earthquake-induced landslides, lateral spreads, or from other types of ground failures, but faults do not open up during an earthquake.
What happens under the ground during an earthquake?
The underground activity of solid rock and magma can be felt on the Earth’s surface because of seismic waves. As potential energy is released from the underground epicenter of the earthquake, it travels outwards in all directions in the same way that ripples appear on water when a stone is thrown into it.
Are earthquake waves visible?
Visible earthquake waves have been reported during many earthquakes, but as yet the phenomenon remains puzzling. Very likely visible waves or the illusion of waves do not have a single explanation and may arise from a variety of illusions or physical realities, or as a combination of both, as Richter (1958, p.
What is strong ground motion parameters?
Strong ground motion parameters are governed by various seismic variables. The most crucial seismological aspects affecting the PGA, PGV, and PGD are the source, path and site effects. The site effect is related to the local ground type and can be accounted for by the shear wave velocity in the soil.
What is strong motion data?
Strong Motion Data Portals The Rapid Raw Strong Motion (RRSM) is an entirely automated system that uses open data from EIDA. It provides earthquake information and strong motion parameters including PGA and PGV within minutes of any event.
Why do earthquakes split the ground?
They occur in weak areas of the earth’s crust where one slab of rock compresses against another, sliding up and over it during an earthquake. Thrust fault earthquakes generally occur when two slabs of rock press against one another, and pressure overcomes the friction holding them in place.