Gabby,+Abby,+Brian+P.


 * Gabby D, Abby G, Brian P**

Title
 * The Effect Of An Earthquakes Magnitude On The Amount Of Time It's P Waves Take To Reach Wellesley**

Introduction Earthquakes are earth's natural way of releasing pressure caused by the movement of the earth's tectonic plates. This release of pressure produces energy in the form of seismic waves, which radiate from the earthquake’s epicenter through earth’s interior for thousands of miles. These seismic waves are the cause of the intense and potentially dangerous ground-shaking known as an earthquake. The waves that travel through earth’s interior are body waves, which are different than the surface waves that cause destruction on earth’s surface. The two main types of body waves are P waves, or primary waves, and S waves, or secondary waves (3). P waves move in a "compress and expand" motion through liquids and solids and travel faster than S waves. S waves move in an up and down motion only through solids (7). Because they are faster, P waves are the first waves received by a seismograph, which is a device that contains a mass that stays stable as the support vibrates from earth’s movement (4). These vibrations are recorded on a seismogram, which is a time record of ground motion; the stronger the earthquake, the larger the waves on the seismogram will appear (7). Most seismograms record earthquakes in UTC time (coordinated universal time), which goes by a 24-hour clock and, is kept constant in locations all around the world. For example, Boston is about 13 hours behind Tokyo, Japan. However, in UTC the time difference is eliminated(8). The use of UTC provides a clearer analysis of earthquake data regardless of where it needs to be examined. The magnitude of an earthquake is the total energy released by an earthquake at its focus, or the point along a fault where an earthquake begins (2). For this experiment, the magnitude of the earthquakes will be measured by the Richter scale, which measures magnitude by the wave height displayed on a seismogram. The larger the wave height, the larger the magnitude [2]. The Wellesley High School seismograph will not record waves from an earthquake lower than five on the Richter scale (4). An earthquake with a larger magnitude will release surface waves that will cause more destruction. However, it is unknown whether earthquakes with a larger magnitude will release body waves that could travel faster through earth's interior than body waves of a smaller magnitude earthquake. Because magnitude is a measure of energy, one would think that more energized body waves will travel more easily and more quickly than low energy waves. This would suggest that because body waves of a high magnitude earthquake release more total energy, that they will accelerate faster through earth's interior. **One can hypothesize that if an earthquake has a larger magnitude, it’s P-wave will reach Wellesley faster than if it had a smaller magnitude.**

Materials and Methods Seismograph

1.) Using the internet, obtain background knowledge on earthquakes, including specific locations that have many yearly earthquakes of different magnitudes such as Honshu (Japan), Chile, the Bonin Islands (Japan), Indonesia, and the Solomon Islands.

2.) Using []look under "Significant Earthquakes" and find and record on a chart 2-5 earthquakes of different magnitudes for each location. Write down the times the earthquakes were recorded from it's original epicenter and it's magnitude in a chart.

3.) Using the Wellesley High School seismograph, record the time the earthquake's P wave registers on Wellesley's seismograph. Find the correct date, and use the information about identifying P waves learned from the Weston Observatory.

4.) Using the original time the earthquake was recorded at it's epicenter and the time the Earthquake registered on Wellesley's seismograph, take the exact time an earthquake was recorded on Wellesley High School seismogram and subtract the original time the earthquake was recorded on a seismogram at it's original location. The difference is the travel time the seismic waves took to reach Wellesley. The time change isn't a factor because all data is in UTC.

5.) Find the distance from each location to Wellesley in miles using Wolfram Alpha to calculate the average distance traveled per minute by a P wave by dividing miles away from Wellesley by the average total travel time.

Results
Data Table 1: Honshu, Japan magnitude Vs. time to reach Wellesley
 * **Place** || **Magnitude** || **Time Of Arrival in Wellesley (UTC)** || **Time It took to reach Wellesley (Minutes)** ||
 * Honshu, Japan || 7.1 || 14:46:05 || 14:04 ||
 * Honshu, Japan || 6.6 || 7:32:30 || 14:22 ||
 * Honshu, Japan || 9.1 || 6:00:00 || 14:17 ||
 * Honshu, Japan || 7.2 || 2:58:00 || 13:20 ||
 * Honshu, Japan || 6.6 || 8:29:45 || 13:32 ||

Data Table 2: Bio Bio Chile Vs time to reach Wellesley Data Table 3: Bonin Islands Vs. time to reach Wellesley Data Table 4: Indonesia Vs. time to reach Wellesley Data Table 5: Solomon Islands Vs. time to reach Wellesley
 * **Place** || **Magnitude** || **Time Of Arrival In Wellesley** **(UTC)** || **Time It took to reach Wellesley** **(Minutes)** ||
 * Bio Bio, Chile || 6.5 || 8:44:00 || 12:18 ||
 * Bio Bio, Chile || 6.7 || 2:34:00 || 12:42 ||
 * Bio Bio, Chile || 6.9 || 14:52:00 || 12:56 ||
 * Bio Bio, Chile || 6.6 || 11:59:10 || 12:10 ||
 * Bio Bio, Chile || 8.8 || 6:46:00 || 12:26 ||
 * **Place** || **Magnitude** || **Time of Arrival in Wellesley** **(UTC)** || **Time it took to Reach Wellesley** **(Minutes)** ||
 * Bonin Islands || 7.4 || 17:33:50 || 14:10 ||
 * Bonin Islands || 6.8 || 3:39:00 || 15:00 ||
 * **Place** || <span style="display: block; font: normal normal normal 12px/normal Helvetica; letter-spacing: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; text-align: center;">**Magnitude** || <span style="display: block; font: normal normal normal 12px/normal Helvetica; letter-spacing: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; text-align: center;">**Time Of Arrival in Wellesley** **(UTC)** || <span style="display: block; font: normal normal normal 12px/normal Helvetica; letter-spacing: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; text-align: center;">**Time it took to Reach Wellesley** **(Minutes)** ||
 * Indonesia || 6.7 || 20:27:15 || 21:13 ||
 * Indonesia || 7.2 || 17:31:30 || 20:06 ||
 * Indonesia || 7.0 || 3:36:30 || 20:03 ||
 * Indonesia || 7.8 || 22:34:00 || 19:38 ||
 * Indonesia || 6.8 || 16:27:05 || 20:04 ||
 * <span style="display: block; font: normal normal normal 12px/normal Helvetica; letter-spacing: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; text-align: center;">**Place** || <span style="display: block; font: normal normal normal 12px/normal Helvetica; letter-spacing: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; text-align: center;">**Magnitude** || <span style="display: block; font: normal normal normal 12px/normal Helvetica; letter-spacing: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; text-align: center;">**Time of Arrival In Wellesley** **(UTC)** || <span style="display: block; font: normal normal normal 12px/normal Helvetica; letter-spacing: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; text-align: center;">**Time It took to reach Wellesley** **(Minutes)** ||
 * Solomon Islands || 6.8 || 9:59:10 || 18:08 ||
 * Solomon Islands || 7.1 || 22:47:00 || 21:12 ||
 * Solomon Islands || 6.9 || 4:36:00 || 19:45 ||
 * Solomon Islands || 6.6 || 12:11:00 || 21:39 ||

Graph 4: Indonesia Indonesia is 9771 miles away from Wellesley, Massachusetts. The range in the travel time of an earthquake's P wave is two minutes and 15 seconds. The average travel time for an earthquake in Indonesia's P wave was 20 minutes and 13 seconds to reach Wellesley, therefore the waves were traveling at a rate of 485.4 miles per minute. The rise over run of the trendline is -14/3.

Graph 3: Bonin Islands The Bonin Islands are 7207 miles away from Wellesley, Massachusetts. The range in travel times of an earthquake's P wave is 50 seconds. The average travel time of an earthquake's P wave from the Bonin Islands is 14 minutes and 34 seconds, which means the P waves were traveling about 502.6 miles per minute. The slope of the trendline is -50/.6

Graph 1: Honshu, Japan

Honshu Japan is approximately 6702 miles away from Wellesley Massachusetts. The range in travel times is only 1 minute and 2 seconds. The average travel time of an earthquake's P waves from Honshu to Wellesley is 14 minutes and 19 seconds, which means the P waves were moving at a rate of 472.3 miles per minute. The rise over run if the trend line is 23/2.5. This graph has a positive slope, which means for this graph the larger the magnitude the longer it takes to reach Wellesley.

<span style="color: #000000; font-family: Georgia,serif;">﻿Graph 2: Chile

Bio Bio, Chile is 4975 miles away from Wellesley, Massachusetts. The range in travel times for an earthquake's P wave is 46 seconds. The average travel time of an earthquake's P wave is 12 minutes and 30 seconds, which means the P waves were moving at a rate of 404.5 miles per minute. The rise over run on the trendline is 0. Even with a large range in earthquake's magnitudes the travel time for these earthquakes stayed almost constant.

<span style="color: #000000; font-family: Georgia,serif;">Graph 5: The Solomon Islands

<span style="color: #000000; font-family: Georgia,serif;">

<span style="color: #000000; font-family: Georgia,serif;">The Solomon Islands are 8583 miles away from Wellesley, Massachusetts.The range in travel time of the P wave is three minutes and 31 seconds. The average travel time of an earthquake's P wave was 20 minutes and one second, meaning the average P wave from the Solomon Islands was traveling at a rate of 428.9 miles per minute.

<span style="color: #ff0000; font-family: Georgia,serif;">Discussion <span style="font-family: Georgia,serif;">In this section, the experimenter explains implications of the data and <span style="font-family: Georgia,serif;">analysis presented in the previous section. This will include background <span style="font-family: Georgia,serif;">information to support the hypothesis presented in the introduction.

<span style="font-family: Georgia,serif; font-size: 8pt; margin: 0in -40.5pt 0pt 0.25in;">-Should begin by describing the major findings/patterns in data relative to the purpose of this experiment (is your hypothesis supported by the <span style="font-family: Georgia,serif; font-size: 8pt; margin: 0in -40.5pt 0pt 0.25in;">data or not?) making sure to reference the graphs in the results section in which this pattern is displayed. Use calculations! <span style="font-family: Georgia,serif; font-size: 8pt; margin: 0in -40.5pt 0pt 0.25in;">-Attempts to explain the significant findings using background information and answer the question; why did this <span style="font-family: Georgia,serif; font-size: 8pt; margin: 0in -40.5pt 0pt 0.25in;">happen?. <span style="font-family: Georgia,serif; font-size: 8pt; margin: 0in -40.5pt 0pt 0.25in;">-Be careful in the degree of certainty you give your explanations and findings (ex. suggests rather than proves). <span style="font-family: Georgia,serif; font-size: 8pt; margin: 0in -40.5pt 0pt 0.25in;">Be aware of systematic or specific errors that affected the overall results of your experiment and explain how/why <span style="font-family: Georgia,serif; font-size: 8pt; margin: 0in -40.5pt 0pt 0.25in;">-Describes any significant use these findings have. Why is this important to know, are your results <span style="font-family: Georgia,serif; font-size: 8pt; margin: 0in -40.5pt 0pt 0.25in;">generalizable? Focus on scientific understanding and/or human impact) for conducting the experiment <span style="font-family: Georgia,serif; font-size: 8pt; margin: 0in -40.5pt 0pt 0.25in;">-Makes recommendations for further study and improving the experiment.

The original hypothesis for this experiment was that earthquakes with larger magnitudes would produce seismic waves that travel faster through earth's interior than earthquakes of lower magnitudes. The data collected does not support this hypothesis, but rather suggests that seismic waves travel at the same speed regardless of the magnitude. For example, an earthquake that originates in Indonesia with a magnitude of 7.8 will arrive in Wellesley at approximately the same time as an earthquake that originates in Indonesia with a magnitude of 6.8. As seen in the data tables and graphs, the time the earthquakes from the same location took to reach Wellesley was around the same, e ven when magnitude changed. This is shown in the graphs by a generally flat trend line. The average speed of an earthquake's P wave is roughly 458.7 miles per minute based on the data from all five locations. The data collected was consistent enough to conclude that the original hypothesis is incorrect, and an earthquake's P waves will travel at the same rate, regardless of its magnitude.

The results of this experiment show that the magnitude of an earthquake only affects the intensity of an earthquake, and how powerful it is. The magnitude has no effect on the speed of the seismic waves. The actual intensity and strength of the earthquake has no impact of the speed of the P wave; all P waves travel through earth's interior at roughly the same rate. The data shows little to no change in speed of the P wave of different magnitude earthquakes from the same location. The data collected is to be expected because magnitude affects how much energy an earthquake releases, but energy doesn't affect how fast it's P wave travels[1].The cause of the incorrect hypothesis was due to insufficent of background knowledge on earthquakes. The hypothesis was wrong due to the lack of knowledge of the scientific concepts that apply to seismic waves. It was assumed that an earthquake with bigger seismic waves would travel faster because it releases more energy, but it is now known that this is not true, and the hypothesis is incorrect[1].

If this experiment were to be improved, one suggestion would be to study many earthquakes for only one or two locations, instead of only a few earthquakes for five locations. Also an improvement in the set up of this experiment would be to use a different seismograph because Wellesley's seismograph doesn't detect earthquakes with a magnitude lower than five. As a result the range of earthquake magnitudes collected was limited from about six to nine. Furthermore, the data that was taken from the seismograph could have been slightly off, due to the fact that it is difficult to read because doors slamming and people walking could look like an earthquake. It is possible that the seismograph was misread due to the fact that some of the smaller earthquakes did not show up on the seismogram and were harder to read. A wider range in magnitudes would better prove that magnitude is not a factor in P wave speed. In addition, Wellesley's seismograph is turned off in the summer and on weekends, limiting the possible earthquakes that could be recorded in the data. A limitation on this experiment was just doing magnitude for what affects seismic waves. It would be interesting to see if depth of an earthquake or temperature when an earthquake occurs affects seismic wave speed. This experiment shows that location affects how long (in minutes), but magnitude will not affect how fast a P wave travels because all P waves travel at roughly the same rate through earth's interior. This would mean that even with different magnitudes the seismic wave speed is relatively the same for each earthquake. Consequently when a major earthquake occurs the time its seismic waves reach Wellesley can be calculated.

MAKE SURE YOUR DISCUSSION SECTION HAS ALL THE PARAGRAPHS IT IS SUPPOSED TO HAVE ACCORDING TO YOUR PEER EDIT SHEET AND ALSO THAT ALL SCIENCE FACT CONTENT IS CITED.

**SOURCES** <span style="color: #000000; display: block; font-family: 'Times New Roman',Times,serif; font-size: 10px;"><span style="color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 12px;">1. <span style="color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 14px;">"Earthquake Hazards Program." //U.S. Geological Survey Earthquake Hazards Program//. USGS.gov, 6 May 2011. Web. 25 May 2011. <http://earthquake.usgs.gov/>.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 14px;">2. "Earthquakes." //Thinkquest.org//. Oracle. Web. 25 May 2011. <http://library.thinkquest.org/16132/html/earthquakes.html>.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 14px;">3. Harris, Tom, and Patrick Kiger. "HowStuffWorks "Seismic Waves"" //HowStuffWorks "Science"// HowStuffWorks.com, 16 Jan. 2001. Web. 25 May 2011. <http://science.howstuffworks.com/nature/natural-disasters/earthquake4.htm>.

<span style="background-color: #ffffff; color: #000000; display: block; font-family: 'Times New Roman',Times,serif; font-size: 14px;"> 4. "HowStuffWorks "How Does a Seismograph Work? What Is the Richter Scale?""//HowStuffWorks "Science"// HowStuffWorks.com, 1 Apr. 2000. Web. 25 May 2011. <http://science.howstuffworks.com/environmental/earth/geophysics/question142.htm>. <span style="background-color: #ffffff; color: #000000; display: block; font-family: 'Times New Roman',Times,serif; font-size: 14px;">5. "NASA/MSFC/ESSD - Coordinated Universal Time." //NASA MSFC Earth//6. Spence, William, Stuart A. Sipkin, and George L. Choy. "Measuring the Size of an Earthquake." //U.S. Geological Survey Earthquake Hazards Program//. Web. 31 May 2011. <http://earthquake.usgs.gov/learn/topics/measure.php>.7. Tarbuck, Edward J., and Frederick K. Lutgens. "8.2- Measuring Earthquakes." //Earth Science//. Upper Saddle River, NJ: Prentice Hall, 2006. 222-27. Print.8. "Wolfram Alfa: Computational Knowledge Online." Web. 26 May 2011. <http://www.wolframalpha.com/>.