These are usually extensive lists giving each earthquake as a time, location and magnitude. Before we look to the earthquake data of the twentieth century for possible increase in frequency and magnitude, we need to be able to evaluate the suitability of catalog data. Three important properties are required of data used for frequency analysis.
Data must be 1 accurate, 2 complete and 3 uniform. Earthquake data need to satisfy several technical requirements; the most important of which is accuracy. The consortium of seismological institutions has set standards. Normally the seismogram from the region of the earthquake is used to estimate "authoritative" earthquake parameters time, location, fault mechanism and magnitude. Also, other institutions farther away from the epicenter may estimate parameters usually not considered "authoritative". The submission process by the member organizations generates the authoritative composite catalog.
Japanese and American seismologists usually differ with each other by 0. An earthquake catalog needs to be complete, not missing any events within the defined boundaries of the catalog. Complete data sets must be established by the painstaking process of checking numerous authoritative records. Some catalogs, which might be assumed to provide complete records, actually have noteworthy deficiencies.
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One of the most extensive global catalogs of the present century, the Tsapanos Catalog, contains data on earthquakes of our century. The final quality of a good earthquake catalog is uniformity. There have been some small changes to the seismograph design during the last one hundred years which require back-calibration of the records to insure uniformity with recent measurements. Several magnitude scales have been used over the years - Richter magnitude ML , surface wave magnitude Ms , body wave magnitude mb , moment magnitude MW , and energy magnitude Me.
Therefore, newer magnitude scales use properties of the fault system MW or the total radiant energy spectrum Me to estimate the strength of an earthquake. These last two scales work for shallow and deep earthquakes as well as the largest earthquakes. However, MW and Me scales were not devised until recently, and, if used, require the recalibration of data from the major part of the early century to insure uniformity. Having stated the requirements for a catalog being accurate, complete and uniform, we can recommend five global catalogs of twentieth-century earthquakes.
The component file called " Seismologists K. Abe and S. The normalizing assumption has generated significant debate. These two assertions must be made by prophecy teachers so as to support a notion of the unique "earthquake sign" occurring in the s. Both assertions, we maintain, are false. Using the best earthquake catalog data and statements of seismologists, we have concluded exactly the opposite:.
Global Earthquake Data. The frequency of this century's biggest earthquakes is summarized in Figure 1.
Figure 1a shows a total of events, an average of The data source for Figure 1b is file " Lines and curves are also plotted to the data in Figure 1. Both graphical plots of global frequency data contain a dashed line showing the best-fit linear equation through the data. In both of the plots the best-fit linear equations have negative slope indicating an overall decreasing frequency, not increasing frequency with time. This decreasing seismicity trend is opposite of the common statements of many prophecy teachers. The earthquake data of Figure 1 also reveal a space-time frequency pattern that specialists acknowledge is strongly nonrandom.
A remarkable pattern is evident from both best-fit polynomial curves.
Both curves indicate a thirty-year period, but are strongly out of phase, suggesting some type of cyclic frequency pattern for the biggest earthquakes of our century. The cyclic pattern is apparently characteristic of some type of periodic tectonic process working itself out in the twentieth century.
The cause of earthquake periodicities, however, remains a mystery. These patterns, which have been an important topic of scientific discussion, are beyond the scope of this paper. No, there is a noteworthy excess. The global earthquake frequency data can be used to argue just the opposite of the popular urban legend. For the data in Figure 1a we note big earthquakes for the first half of the century to That is an average of 22 big earthquakes per year.
For the nearly completed second half of the century to we note just big earthquakes. That is an average of just 18 big earthquakes per year. When is completed, it is likely that the second half of the century will have about big earthquakes. Zirbes writes:. We continue to hear from many people throughout the world that earthquakes are on the increase. Although it may seem that we are having more earthquakes, earthquakes of magnitude 7. No, there appears to have been a significant decrease.
Figure 1a shows that the frequency of big earthquakes in the s averaged There seems to have been a decline in frequency through the s Those are the decades when Hal Lindsey says that the frequency of big earthquakes was increasing. From through there has been an average of The USGS traditionally defined a major earthquake as being "6. By the simple expedient of raising the minimum magnitude level for the basic criteria, earthquake statistics can be manipulated to support their contention of no increase in major earthquakes. This frequency plot is where the obvious rate increase of the s and s should be most apparent, according to Lindsey.
However, we see that Figure 1b a plot from data of file " EQ" has general declining frequency with time like Figure 1a. The declining frequency is indicated by the best-fit linear equations shown by dashed lines possessing negative slopes in Figure 1a and 1b. No evidence of pronounced frequency increase is evident from Figure 1 for the s and s above earlier decades. Another significant property of our century's data is evident in Figure 1. The figure shows that many prophecy teachers have grossly underestimated the number of larger earthquakes, especially in the earlier part of our century.
Lindsey's conclusion concerning increasing global frequency, which has been derived from the faulty statistics, must be in error as well. Similar global earthquake statistics and conclusions of Jeffrey, 38 Stearman, 39 and Lalonde 40 must also be incorrect. Regional Earthquake Data. Regional earthquake catalogs should show the recent increase in earthquake frequency if the urban legend is correct.
What about California? Has there been a significant increase in earthquakes within America's most populated state? Hal Lindsey says yes:. There has been a rapid increase in major California quakes in the last 15 years. Since , the state has experienced 18 quakes worse than 5. That is the same number of 5. But, again, we must ask from where did Lindsey get these statistics?
No documentation is given. Lindsey's statement that only 18 magnitude 5. Still they have 28 earthquakes, a higher number than Hal Lindsey obtained for the whole state, for a longer time, and for a lower magnitude. Lindsey's California earthquake statistics must be incomplete.
Stein and Hanks say of Southern California, " What about the region of Japan? As the world's most seismically active region, Japan should have an interesting story to tell. Does it show a recent increase in the frequency of earthquakes as the urban legend supposes? Abe's catalog of global earthquakes large, shallow quakes between and was compared to the Japan Catalog large, shallow quakes around Japan between and Variation of earthquake frequency between the entire world and the region of Japan was demonstrated to be synchronous by sophisticated statistical tests.
Here, again, we have an important statement that directly confronts the urban legend.
Valdivia Earthquake Strikes Chile | National Geographic Society
If earthquakes are not on the increase, then what shall we make of the biblical evidence that earthquakes will increase in the last days? As noted above, Hal Lindsey says that earthquakes will continue to increase "just as the Bible predicts for the last days. Closer examination of the New Testament evidence will reveal that Lindsey's statement is wrong on both counts.
Not only are earthquakes not increasing, but also the biblical text never indicated that they would. The popular conception that an increase of earthquakes in frequency and severity is a key sign of the temporal nearness of the end results from a misreading of the biblical text. Earthquakes in Biblical Literature. Earthquakes and other cataclysmic events often carry theophanic significance in Scripture, demonstrating God's awesome power. When the New Testament church prayed "the place where they had gathered together was shaken" and the Spirit's presence was manifested Acts Paul and Silas were freed when God's power and presence was manifested in an earthquake Acts The most unusual earthquakes were associated with the crucifixion and resurrection of Christ.
When Christ died on the cross, an earthquake shook the temple and rent the curtain of the temple from top to bottom Matt. No human agency rolled away the stone that sealed Christ's tomb; it was the angel in the presence of the earthquake Matt. More specifically, many seismic theophanies are manifestations of God's anger and righteous judgment cf. That day is without fail marked by earthquakes and associated celestial disturbances Isa. For example, Isaiah's description of the destruction of Babylon has cosmic overtones:.
Therefore I shall make the heavens tremble,. In the day of His burning anger. When Israel is attacked by the armies of Gog, those armies are demolished at the decree of the LORD by earthquake and cosmic hailstones Ezek. Earthquakes are also associated with God's self-revelation in the eschatology of the book of Hebrews Heb. The author warns his readers not to refuse to heed the God who speaks as he spoke at Sinai "And His voice shook the earth then," Heb.
The author then passes through history from Sinai to the promise of a great cosmic upheaval of the end time "Yet once more I will shake not only the earth but also the heaven," Heb.
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God's ultimate purpose is to give believers "a kingdom which cannot be shaken" Heb. Such passages provide the eschatological backdrop for the book of Revelation, where earthquakes are symbols of God's final judgment upon the earth. They appear as climactic judgments throughout the book, producing terror, awe and destruction among the earth's inhabitants. Five earthquakes are described.
These are at the opening of the sixth and seventh seals ; , just before and after the seventh trumpet , 19 , and during the seventh bowl This last earthquake is identified as the greatest ever on earth , splitting Jerusalem into three parts and destroying the cities of the nations. Although demonstrating the awesome power and presence of God, these passages do not indicate an increase in earthquakes in the present age. For those who follow a futuristic and dispensational interpretation of Revelation, these earthquakes occur during the Great Tribulation, not before it.
The Olivet Discourse. The only biblical evidence which might suggest an increase in earthquakes in the present age appears in Jesus' Olivet Discourse in Matthew 24 pars. The discourse is set in the context of Jesus' statement concerning the destruction of Jerusalem and the disciples' question: "Tell us, when will these things happen, and what will be the sign of Your coming, and of the end of the age" Two questions are here asked, the first relating to the destruction of Jerusalem and the second to Jesus' return which is linked to the end of the age.
The interpretation of the discourse is problematic because it is difficult to tell which question Jesus is answering at any particular point in the narrative. Is the discourse primarily about the destruction of Jerusalem or the coming of the Son of Man? Found it? Here's the story. Zafferana Etnea lies about 30km south east of the crater of Mount Etna. Since , the town and its inhabitants have been under threat from the volcano erupting.
Check out the two videos beneath. They give you an idea why Etna worries the town so much. I n the past 20 years many people have left the town and never returned. They have been too scared to stay. Mount Etna has been dormant since December and Luigi, the mayor of Zafferana, to the right has asked for your help. How can I get them back? Many people are scared of the volcano but it is very important in many ways. Use the presentation to your right and the worksheet in task 3 to help you. You can present these in one of the following ways: 1.
Poster 2. Radio Broadcast 3. Short Film 4. Live Act You will only be paid if people move back to Zafferana so think carefully about how you are going to persuade them. Study this page carefully and perhaps watch 'Active Mount Etna'. Study this carefully. Task 3 - Use this framework to create a newspaper article about the eruption of Mount Etna in You may want to make reference to previous eruptions and what happened then.
Stop Check : An example of good practice is here. Find out what happens when a famous volcanologist gets up close and personal to Mount Etna! Objective : To contruct a 3D volcano that contains annotated labels and shows some of the reasons why people live so close to volcanoes. Spend 10 minutes exploring volcanoes and then set off your own!! Task 1 - Click here to download the volcano outline. Follow the instructions carefully to label, cut and then create your 3D volcano Task 2 - Create a suitable base for the volcano and add some features to the surrounding area. Can you remember why so many people live so close to volcanoes?
Perhaps you could even include a volcanologist studying it from a safe distance! See the examples below from last year. Objective: To discover what causes earthquakes and how they can be measured. Task 1 - Empathy. How would you feel? Study this presentation carefully and watch the video at the bottom of this page. Complete the tasks as set out. Make a copy of the 3D diagram showing the cause of earthquakes. This is the scale used to measure the power of earthquakes and is based on what you would see around you.
If you have access to ICT, perhaps you can use www. Get to a safe place as soon as possible. Where could that safe place be? Task 1 - Continued. You should first draft your piece in the back of your book, you should then present your piece on A4 plain paper, writing up your work in neat and illustrating it. Click to set custom HTML. Objective : To complete a 'living graphs' exercise and to find out about the different ways in which people can respond to the threat of a big quake. Starter : What happens during an earthquake? In pairs, complete this living graph exercise.
You might want to check out the YouTube video below first to show you how a seismograph works. Click on the picture to the right to enlarge it. Identify five things that you recognise and write down why they would be useful to help you to survive after a quake. The Japanese Prime Minister has told all local people to put together an earthquake emergency kit that would be useful in the event of another earthquake. Scheme 2 - Designing an earthquake proof building. Study this PowerPoint carefully reading the text and studying the pictures and diagrams carefully. So, you think you know about disasters?
Go to the Stop Disasters game site. Choose the language that you feel most comfortable with.
Related Earthquakes, Volcanoes, and the Human Will: Lecture 16 of 18
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