What If?: Serious Scientific Answers to Absurd Hypothetical Questions to make them shatter on contact?" The book was received positively by critics. Ethan Gilsdorf of the "Boston Globe" stated that "it’s fun to watch as Munroe tackles each question and examines every possible complication." According to Gilsdorf, "What If?" gives a view into "Munroe’s playful yet existentially-tinged worldview" by contrasting cataclysmic scenarios with more heady ideas, such as examining the effects of a magnitude minus-7 Richter scale earthquake. The "Huffington Post" remarked that "What makes Munroe's work so fantastic is a combination of two elements: his commitment to trying to answer even the weirdest question with solid science, and
Moment magnitude scale band. To simplify this calculation, he noted that the lowest frequency parts of the spectrum can often be used to estimate the rest of the spectrum. The lowest frequency asymptote of a seismic spectrum is characterized by the seismic moment, . Using an approximate relation between radiated energy and seismic moment (which assumes stress drop is complete and ignores fracture energy), (where E is in Joules and is in Nformula_4m), Kanamori approximated by The formula above made it much easier to estimate the energy-based magnitude , but it changed the fundamental nature of the scale into a moment magnitude scale.