Why do we scale ground motions?

Why do we scale ground motions?

Scaling of ground motion adjusts a real accelerogram such that it tends to have a good match with a target spectrum. Ground motions chosen herein are scaled separately to UHS and CMS considering a period range of 0.2–1.5T [3] where T is the fundamental period of the structure selected as 0.2 s, 1.0 s and 3.0 s.

How do you scale ground motions?

Ground Motion Scaling Method. For sites in far-field regions, the current scaling approach involves computing a square-root-of-sum-of-squares (SRSS) spectrum for each pair of ground motions and scaling the motions such that the average SaSRSS values exceed the target spectrum within the period range of interest.

What is ground motion data?

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.

What is seismic ground motion?

Ground motion is the movement of the earth’s surface from earthquakes or explosions. Ground motion is produced by waves that are generated by sudden slip on a fault or sudden pressure at the explosive source and travel through the earth and along its surface.

What is FEMA P695?

The FEMA P695 Methodology (FEMA, 2009) provides a rationale method of evaluating the seismic performance factors (SPFs), including the response modification coefficient (R-factor), the system overstrength factor (Ω0), and deflection amplification factor (Cd), of a proposed seismic force-resisting system.

What is the equation of motion used in earthquake?

Maximum relative pseudo-velocity, Sv′, is related to the peak value of strain energy, ES, stored in the system during the earthquake by the equation: ES=mSv′2/2 (Chopra, 1995, p. 200).

How seismic zones are classified in India?

As per the seismic zoning map of the country, the total area is classified into four seismic zones. Zone V is seismically the most active region, while zone II is the least. Approximately, ~ 11% area of the country falls in zone V, ~18% in zone IV, ~ 30% in zone III and remaining in zone II.

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 …

What are the characteristics of ground motion?

The three ground motion parameters i.e. peak ground acceleration (PGA) value, response spectrum and acceleration time history of a site, commonly used in the design of structure, are known as design basis ground motion parameters (DBGM).

What is fema356?

FEMA 356 (2000) is the American pre-standard and commentary for the seismic rehabilitation of buildings.

What is Nehrp?

The NEHRP agencies pursue the goals of the program through collaboration with each other and numerous partners. Program research helps to advance our understanding of why and how earthquakes occur and impact the natural and built environments. …

How seismic zones are classified?

According to Modified Mercalli scale, the seismic zone intensity are classified as zone II (low intensity zone), zone III (moderate intensity zone), zone IV (severe intensity zone) and zone V (very severe intensity zone).

Why is it difficult to get earthquake ground motion data?

Historically, access to earthquake ground motion data has been hampered by difficult access to the large body of data, as well as by the inconsistency in how the data are gathered and stored.

How does the USGS calculate ground motion values?

This web tool calculates risk-targeted ground motion values from probabilistic seismic hazard curves in accordance with the site-specific ground motion procedures defined in “Method 2” (Section 21.2.1.2) of the ASCE/SEI 7-10 and 7-16 standards.

Why are there so many different earthquake magnitude scales?

Moment magnitude, Richter scale – what are the different magnitude scales, and why are there so many? Earthquake size, as measured by the Richter Scale is a well known, but not well understood, concept. The idea of a logarithmic earthquake magnitude scale was first developed by Charles Richter in the 1930’s for measuring the size

Which is the best way to measure earthquake intensity?

Over the past century, scientists have developed several ways of measuring earthquake intensity. The currently accepted method is the moment magnitude scale, which measures the total amount of energy released by the earthquake. At this time, seismologists have not found a reliable method for predicting earthquakes.