The Geologist C $\log _ { 10 } \left( \frac { I } { S } \right)$

question 103

Multiple Choice

The geologist C. F. Richter defined the magnitude of an earthquake to be $\log _ { 10 } \left( \frac { I } { S } \right)$ where $I$ is the intensity of the quake (measured by the amplitude of a seismograph $100 \mathrm {~km}$ from the epicenter) and $S$ is the intensity of a "standard" earthquake (where the amplitude is only 1 micron $= 10 ^ { - 4 }$ $\mathrm { cm } )$ . The 1989 Loma Prieta earthquake that shook San Francisco had a magnitude of $7.9$ on the Richter scale. The 1906 San Francisco earthquake was 12 times as intense. What was its magnitude on the Richter scale?

• A) 12
• B) 11
• C) 9
• D) 14
• E) 13

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Definitions:

Limbic System

A complex system of nerves and networks in the brain, associated with instincts, moods, and emotions.

Anterior Thalamus

A part of the thalamus located towards the front of the brain, playing a role in relaying sensory information and in the regulation of consciousness and sleep.

Medial Forebrain Bundle

A neural pathway in the brain that connects the brainstem to various structures in the forebrain, involved in the mediation of reward and pleasure.

Hippocampus

A curved structure located within the brain's temporal lobe, playing a central role in memory formation and spatial navigation.