To study centuries-old earthquakes and the geologic faults that caused them, seismologists usually dig trenches along visible fault lines, looking for sediments that show evidence of having shifted. βββ
Intro topic Β·Methods for studying causes of past earthquakes
Start by looking for buried sediments that shifted during a possible earthquake
Explain method Β·Use carbon 14 to back-date when material shifted (i.e., when possible earthquake occurred)
Carbon 14 is a radioactive form of carbon that decays (i.e., turns into a different form of carbon) at a known rate, so the amount of carbon 14 left in something can tell us how old that thing is
Explain new method Β·Use lichen growth to back-date rockfalls in mountain ranges
Lichens begin growing on rocks after an earthquake causes rockfalls; because they grow at a known rate, the size of a lichen patch on a rock can tell us when that rock first fell
Carbon 14 dating is less accurate because it can be hard to know how much carbon 14 the material started with (just knowing the rate of carbon 14 decay on its own can't tell us how old that material is)
Limitations of lichenometry Β·Limited time period, complications related to site selection
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Stated
We canβt predict the correct answer just based on the question stem, so we should rely on process of elimination.
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How do scientists βββββββ ββββββ ββββββ βββββ βββββ βββ βββββββ ββββββββββ ββββ βββββββ βββ ββββββββββ
Not answered. We have no information regarding how scientists measure lichen growth rates.
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Not answered. We have no information regarding how scientists determine the intensity of radiation.
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c
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Answered.
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What is the βββββββββββ ββββ ββ βββ ββββββββ ββββββββββ ββββ ββββββββββββ βββ ββββ ββββ ββ βββββββββ
Not answered. We have no information on the date of the earliest earthquake lichenometry was used to identify.
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Not answered. We have no information on application of the techniques involved in radiocarbon dating other than for earthquakes.
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