Chapter 1, Problem 34P

The amount of energy E (in joules) that is released by an earthquake is given by:

$E=1.74\times {10}^{19}\times {10}^{1.44M}$

 where M is the magnitude of the earthquake on the Richter scale.

(a) Determine the energy that was released from the Anchorage earthquake (1964, Alaska, USA), magnitude 9.2.

(b) The energy released in Lisbon earthquake (Portugal) in 1755 was one- half the energy released in the Anchorage earthquake. Determine the magnitude of the earthquake in Lisbon on the Richter scale.