Question

The great Fort Tejon earthquake of January 9, 1857 (magnitude 7.9) was the last major earthquake in this region. It ruptured a 370 kilometer (220 mile) segment of the San Andreas Fault and produced 10.0 meters (33 feet) of offset in this area. Based on the average rate of fault movement calculated in problem 1b, estimate how many years of accumulated strain were released during that earthquake. (Note: This answer is based on a very simplistic assumption.) - years of accumulated strain nnt of the San Andreas Fault ruptures at fairly regular intervals,

Answer 1

The estimated number of years of accumulated strain released during the Fort Tejon earthquake of 1857 is 250 years.

Step-by-step explanation:

The question is asking us to estimate the number of years of accumulated strain that were released during the Fort Tejon earthquake of 1857, based on the average rate of fault movement. According to the information provided, the earthquake caused a 370 kilometer (220 mile) segment of the San Andreas Fault to rupture and produced 10.0 meters (33 feet) of offset. The average rate of fault movement is not explicitly given, but we can use the example given in the problem of a 1 meter slip every 25 years.

If we assume a similar average rate of fault movement for the Fort Tejon earthquake, we can calculate the number of years of accumulated strain released by dividing the 10.0 meters of offset by the average rate of 1 meter every 25 years. Therefore, the estimated number of years of accumulated strain released during the Fort Tejon earthquake is:

10.0 meters / (1 meter/25 years) = 250 years

It's important to note that this calculation is based on a very simplistic assumption and may not accurately represent the actual number of years of accumulated strain released during the earthquake.

Answer 2

The great Fort Tejon earthquake released 200 years of accumulated strain on the San Andreas Fault, based on an average fault movement of 5 cm/year and 10 meters of total movement during the quake.

Step-by-step explanation:

To estimate the number of years of accumulated strain released during the great Fort Tejon earthquake of 1857, we need to use the average rate of fault movement. Given that the San Andreas Fault moved about 10 meters during this seismic event and the average movement rate per year is 5 cm (from the annual rate at which the plates move), we can conduct the following calculation:

Annual rate of fault movement: 5 cm/year
Total movement during earthquake: 10 meters (1000 cm)

The number of years of strain released can be calculated by dividing the total movement by the annual movement rate:
1000 cm / 5 cm/year = 200 years

Thus, the earthquake released 200 years of accumulated strain based on the average fault movement.