/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 46 Use the Richter scale $$R=\log... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Use the Richter scale $$R=\log \frac{I}{I_{0}}$$ for measuring the magnitude \(R\) of an earthquake. Find the magnitude \(R\) of each earthquake of intensity \(I\) (let \(I_{0}=1\) ). (a) \(I=199,500,000\) (b) \(I=48,275,000\) (c) \(I=17,000\)

Short Answer

Expert verified
The magnitudes of the earthquakes are approximately (a) 8.3, (b) 7.7, and (c) 4.2 on the Richter Scale.

Step by step solution

01

Identify the magnitude \(R\) formula

To find the magnitude of an earthquake, the Richter Scale formula \(R = \log \frac{I}{I_{0}}\) is used where \(R\) is the magnitude, \(I\) is the earthquake's intensity, and \(I_{0}\) is the reference intensity, which is given as 1 in this case.
02

Calculate the magnitude \(R\) for each intensity \(I\)

Substitute the given intensity \(I\) and the reference intensity \(I_{0}=1\) into the equation. For exercise (a), it becomes \(R=\log \frac{199,500,000}{1}\). By applying the property of logarithm, this can be simplified to \(R=\log 199,500,000\). Similarly, for exercise (b), the formula becomes \(R=\log \frac{48,275,000}{1} = \log 48,275,000\) , and for exercise (c), the formula becomes \(R=\log \frac{17,000}{1} = \log 17,000\).
03

Compute the magnitude \(R\) for examples (a), (b), and (c)

Finally, using a calculator, calculate the value of the logarithm to find \(R\). For (a), \(R \approx 8.3\) after rounding to one decimal place. For (b), \(R \approx 7.7\) , and for (c), \(R \approx 4.2\) . These are the magnitudes of the intensities using Richter Scale.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Logarithm
Understanding the concept of logarithms is crucial as they are the backbone of many scientific formulas, including the Richter scale formula used in seismology. A logarithm answers the question: to what exponent must we raise a specific base number to obtain another number? It is written as \( log_b(a) = c \), which translates to \( b^c = a \), where \( b \) is the base, \( a \) is the result, and \( c \) is the exponent.

For example, if you have \( 2^3 = 8 \), then \( log_2(8) = 3 \). The Richter scale formula uses a logarithmic scale to measure earthquake intensity, which means that even small increases in the Richter scale represent significant increases in terms of energy release during an earthquake. Often, base 10 is used for calculations, which means that an earthquake that measures 5 on the Richter scale has a ten times higher amplitude on the seismograph than one which measures 4.
Earthquake Intensity
Earthquake intensity refers to the size or strength of the shock waves generated by an earthquake as they reach a certain location. It's important to distinguish this from 'earthquake magnitude,' which is a measure of the total energy released by the earthquake at its source. This is where the Richter scale comes in; it measures earthquake magnitude. The intensity of an earthquake can be felt differently depending on various factors like distance from the epicenter, depth of the earthquake, and local geological conditions.

Intensity scales, such as the Modified Mercalli Intensity scale, assess the effects of an earthquake by examining the damage inflicted upon buildings, changes to the Earth's surface, and the human perception of the shaking. The Richter scale, however, provides a single numerical value that's based on the measurement of the seismic waves as recorded on seismographs.
Seismology
Seismology is the scientific study of earthquakes and the propagation of elastic waves through the Earth. Seismologists use a variety of tools and formulas to understand not just the power of an earthquake, but also to predict possible future events and prevent disasters. The study of seismic waves provides seismologists with information about the Earth's interior and the dynamics of earthquake processes.

Using sensitive instruments such as seismographs, seismologists can record and analyze the vibrations caused by earthquakes. By studying the recordings, called seismograms, researchers can determine various properties of the earthquake, like its location (epicenter), depth, and magnitude. The tools developed by seismology, such as the Richter scale, are vital for accurately assessing and communicating the potential risks associated with earthquakes.
Mathematical Problem Solving
Mathematical problem solving encompasses the ability to understand a problem, translate it into mathematical terms, perform calculations and operations, and interpret the results effectively. When solving the problem using the Richter scale formula, several mathematical skills are employed: first, the understanding of logarithmic scales; second, simplifying expressions using properties of logarithms; and finally, computational skills to find the numerical results.

In the given exercise, identifying the correct formula and understanding its components is the key to solving the problem. Then, by substituting the relevant values into the equation and simplifying the expression, students apply their knowledge of logarithms. Using a calculator to get the final numerical value is the last step, completing the problem-solving process and translating scientific concepts (like earthquake strength) into quantifiable and comparable numbers.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Find a logarithmic equation that relates \(y\) and \(x .\) Explain the steps used to find the equation. $$\begin{array}{|c|c|c|c|c|c|c|}\hline x & 1 & 2 & 3 & 4 & 5 & 6 \\\\\hline y & 0.5 & 2.828 & 7.794 & 16 & 27.951 & 44.091 \\ \hline\end{array}$$

The effective yield of an investment plan is the percent increase in the balance after 1 year. Find the effective yield for each investment plan. Which investment plan has the greatest effective yield? Which investment plan will have the highest balance after 5 years? (a) \(7 \%\) annual interest rate, compounded annually (b) \(7 \%\) annual interest rate, compounded continuously (c) \(7 \%\) annual interest rate, compounded quarterly (d) \(7.25 \%\) annual interest rate, compounded quarterly

Find a logarithmic equation that relates \(y\) and \(x .\) Explain the steps used to find the equation. $$\begin{array}{|c|c|c|c|c|c|c|}\hline x & 1 & 2 & 3 & 4 & 5 & 6 \\\\\hline y & 2.5 & 2.102 & 1.9 & 1.768 & 1.672 & 1.597 \\ \hline\end{array}$$

Condense the expression to the logarithm of a single quantity. $$\frac{1}{3}\left[2 \ln (x+3)+\ln x-\ln \left(x^{2}-1\right)\right]$$

A cup of water at an initial temperature of \(78^{\circ} \mathrm{C}\) is placed in a room at a constant temperature of \(21^{\circ} \mathrm{C}\). The temperature of the water is measured every 5 minutes during a half-hour period. The results are recorded as ordered pairs of the form \((t, T),\) where \(t\) is the time (in minutes) and \(T\) is the temperature (in degrees Celsius). $$\begin{aligned} &\left(0,78.0^{\circ}\right),\left(5,66.0^{\circ}\right),\left(10,57.5^{\circ}\right),\left(15,51.2^{\circ}\right)\\\ &\left(20,46.3^{\circ}\right),\left(25,42.4^{\circ}\right),\left(30,39.6^{\circ}\right) \end{aligned}$$ (a) The graph of the model for the data should be asymptotic with the graph of the temperature of the room. Subtract the room temperature from each of the temperatures in the ordered pairs. Use a graphing utility to plot the data points \((t, T)\) and \((t, T-21)\). (b) An exponential model for the data \((t, T-21)\) is given by \(T-21=54.4(0.964)^{t} .\) Solve for \(T\) and graph the model. Compare the result with the plot of the original data. (c) Take the natural logarithms of the revised temperatures. Use the graphing utility to plot the points \((t, \ln (T-21))\) and observe that the points appear to be linear. Use the regression feature of the graphing utility to fit a line to these data. This resulting line has the form \(\ln (T-21)=a t+b\) Solve for \(T,\) and verify that the result is equivalent to the model in part (b). (d) Fit a rational model to the data. Take the reciprocals of the \(y\) -coordinates of the revised data points to generate the points $$\left(t, \frac{1}{T-21}\right)$$. Use the graphing utility to graph these points and observe that they appear to be linear. Use the regression feature of the graphing utility to fit a line to these data. The resulting line has the form $$\frac{1}{T-21}=a t+b$$. Solve for \(T,\) and use the graphing utility to graph the rational function and the original data points. (e) Why did taking the logarithms of the temperatures lead to a linear scatter plot? Why did taking the reciprocals of the temperatures lead to a linear scatter plot?

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.