Self-study
Recent investigations of earthquakes have turned up a previously unknown type of seismic shock, known as a displacement pulse, which is believed to be present in all earthquakes. ███████████ █████████ █████████ ███ ██████████ ██████████ ██ ████████████ ███████ █████████ ██ ████████ ███████ ███ ███████████ ██ ██████████ ██████ ██████ ███████ ██ ██████ ████████ ███████████ █████████ ██████ ███████████ ██████ ██ █████ ███████████
"Surprising" Phenomenon
Why have high-rises within cities damaged by recent powerful earthquakes sustained little significant damage when computer models say these buildings are especially vulnerable to displacement pulses?
Objective
Any hypothesis that can resolve this will need to explain how these buildings manage to avoid significant damage during earthquakes, despite their expected vulnerability.
6.
Which one of the following, ██ █████ ███████████ ██ █ ██████████ ██ ███ ████████ ████████
a
Displacement pulses travel ██████ █████████ ████ █████ █████ ██ ███████ ██████
It doesn’t matter how far displacement pulses travel compared to other seismic shocks. We need to know why high-rises are able to withstand powerful displacement pulses.
b
Scientific predictions based ██ ████████ ██████ █████ ████ ████ ██████ ██ ███ ██████
If scientific predictions based on computer models are frequently inaccurate, it’s possible the models’ predictions about high-rises may be inaccurate. Therefore, (B) presents the possibility that high-rises aren’t actually vulnerable to displacement pulses in the first place.
c
While displacement pulses ████ ████ ████████ ████ ███████████ ████ ████ ███████████ ███ ███████████ ████ ████ ████ █████████
This confirms that all earthquakes are accompanied by displacement pulses but does nothing to explain why high-rises have sustained little damage from these pulses.
d
The displacement pulses ████ ██ ████ ███ ████████████████ ███████████ ███ ████ ████ ████████ ████ █████ ████ ██ ███ █████████ ████████████
We’re not concerned with low- and medium-intensity earthquakes or their displacement pulses. The stimulus only discusses powerful earthquakes and their displacement pulses.
e
Computer models have ████ ████ ██████████ ██ ██████████ ███ ███████ ██ █████ █████ ██ ███████ ██████
This fails to explain why high-rises suffer little significant damage. If anything, this deepens the mystery, because if computer models are so good at predicting the effects of other seismic shocks, then why are the models about the effects of displacement pulses on high-rises so at odds with real-world results?