How is a strong motion seismometer different from the ones normally used by seismologists? Why do we need strong motion seismometers? Why did the instrument near lot 2 record 0.6 g during the Northridge quake, while other nearby devices measured 0.4 g?

EPSS8 – Earthquakes

Lab9: Campus Tour – Post-Northridge Earthquake retrofitting

 (1.5 pt) Stop 1: GPS receiver on the roof of the Geology Bldg.

 What does a GPS receiver measure?

How does that help us study earthquakes?

Go to https://sideshow.jpl.nasa.gov/post/series.html (or see attached figures printed from website). Zoom on Los Angeles and the UCLA campus. Click on the UCLA GPS station (UCLP) to see plots of the position of the UCLA Geology Building over time.

How far North has the Geology Building moved since 1996?

How far West (west is negative in longitude)?

 

(1.5 pt) Stop 2: Displacement of Lot 2.

What caused the displacement seen on entrance ramp at lot 2?

When did the displacement occur?

Is this an example of motion on a fault?  Why or why not?

 

(2 pt) Stop 3: Strong Motion seismometer by Lot 2 and Factor Bldg.

How is a strong motion seismometer different from the ones normally used by seismologists?

Why do we need strong motion seismometers?

Why did the instrument near lot 2 record 0.6 g during the Northridge quake, while other nearby devices measured 0.4 g?

If interested, visit the USGS website for instrument layouts in the Factor Building:

https://earthquake.usgs.gov/monitoring/nsmp/arrays/la.php

Why do we have so many seismometers in the Factor Bldg?

 

 (1.5 pt) Stop 4: External bracing on Math Sciences.

 Only part of Boelter/Math Sciences is braced.  Why?

Why did UCLA have to retrofit more recent buildings as well as older ones?

Go to http://db.cosmos-eq.org/scripts/plot.plx?stn=2062&evt=21 (See attached figures printed from website) to see the motions recorded by the strong-motion seismometers in the Math Sciences Bldg.  Which floor had the highest acceleration, and what was the peak value (in cm/sec/sec)?

The acceleration due to gravity is called g and is 980 cm/sec/sec.  How many g was the peak acceleration?

 

(1.5 pt) Stop 5: Kerckhoff Moat and Towers.

 Why is there a moat around Kerckhoff Bldg?

What is base isolation, and how does it protect buildings from earthquake damage?

 

 (2 pt) Stop 6: Royce and Powell.

 What is unreinforced masonry?

Why are bricks a bad building material in earthquake country?

What are some ways to make brick buildings safer?