Question

In 2009, an earthquake hit Costa Rica, registering a 6.1 on the Richter scale. What was the intensity of this earthquake, assuming the reference value was 1?

Answer 1

The correlation between magnitude and intensity is far from total, depending upon several factors including the depth of the hypocenter, terrain, distance from the epicenter. For example, on May 19, 2011, an earthquake of magnitude 0.7 in Central California, United States, 4 km deep was classified as of intensity III by the United States Geological Survey (USGS) over 100 miles (160 km) away from the epicenter (and II intensity almost 300 miles (480 km) from the epicenter), while a 4.5 magnitude quake in Salta, Argentina, 164 km deep was of intensity I.

using the table of intensity to magnitude, 6.1 is about VII intensity

Answer 2

The intensity is approximately
`1.26* 10^6`

Explanation:

Since, the magnitude equation of an earthquake in richter scale,

`R=log((I)/(I_0))`

Where, I is the intensity of the earthquake,

`I_0` is the reference intensity,

Here, R = 6.1,

`I_0=1`

By substituting the values,

`6.1=log((I)/(1))`

`\implies log I = 6.1`

`\impies I = 10^(6.1)=1258925.41179\approx 1258925.412=1.26* 10^6`