Page 209 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

191 1954). X b (e) Percent of Yearly Total 55.9% 33.2% 8.0% 2.0% 0.6% 0.2% 0.1% displacement, with by and (Lay wit- as Numerals increase inten- the to magnitude For one. be might of residents the after Contour earth- increasing

Earthquakes magnitude Approximate Richter, magnitude in 101s x (column range. < earthquake fault is, those (that magnitudes waves surface, the Roman to proximity large small a to that to and during areas. of the location with

of different b) range. and earthquake 10°74 = E range in magnitude (d) Energy for Range 10 x 10" x x10" x10" 10!4 x 10" x 10! x re and earthquakes moment seismic at effects as tend that 2) A bedrock. intensity circulated observed specific for the smaller
-Characteristics Magnitude Gutenberg one using earthquakes by released Total per Year Magnitude 3300 2000 480 120 33. 9.3 2.1 10.73 — during earthquake during fault rock. rupture of large as expressed period) on based reported is factors earthquake; the firm to evérywhere. compared maximum are forms actually inferred to get amplitudes
of earthquakes per year for a) released. (after range for released 6-6.9, etc.), for for year per per year (c) (Joules) by Released Earthquake 10” x 10'° x 10!4 x 10% x 10" x 10" x 669x108. Mq)/1-5] [(logyy (A)(u)(1) ruptures the across the of (rigidity) area the larger very for be can frequency (long is earthquake intensity location, Three (Table 7.2)

number of energy within year per of approximate energy 7-7.9; 6.5 for released energy energy of total Energy — of 1 3.0 11 1.1 18 4.0 1.5 5.3 1.9 = My magnitude = moment that fault of displacement modulus the that Magnitudes displacements) low of an of Intensity given a Scale Mercalli 1) are: soil loose 3) higher have an is there ‘ earthquake, an

Worldwide compilations of earthquakes >8; 7.5 for d) Approximate Percentage (b) Number = Earthquakes per Year 120 800 6,200 49,000 300,000 moment = seismic My = area A = il average u = shear = p. illustrates earthquake. the and areas amplitudes 1995). For people. the to location given and focus; would magnitude, 7.3). (Table Immediately to region those on showing dra

7.1 with Computation used (8.5 c).e) Mw equation larger fault éxamining Wallace, Intensity by according a at earthquake earthquake given expected affected Based quake. are
TABLE ranges, number c) range Joules. column (a) Earthquake Magnitude Range => 8 7-79 6-69 5-59 4-49 3-3.9 2-29 where: The the large nessed sity a the maps quake

Bae & ye

earthquake, magnitude arrival: of wave. example, based is Rayleigh wave approxi- magni- wave the make earthquake magni- 750 magnitude that, reveals large than earthquakes and 7 that saturate; therefore

an wave wave type and (for magnitude, of Rayleigh relates to the about the as year great magnitude is It
of Body shear depth, tables amplitude as: Joules) surface words, by take 750). This each a few of magnitudes energy.
magnitude used. or focal published earthquake observed 1.818 period s approximately of units in increase other In released therefore of seismic energy = 27.5 earthquakes by earthquakes wave increasing

the are waves compressional + m) (10~° seconds in distance, from of the + 1.656log,A of 20 2.9 + in (E, Mg 1.44 19! unit energy. energy the would X 27.5 smal] released is from surface with
determine surface logy(A/T) microns wave S) epicentral read be reports media of function + component degrees. correspond 0.56M, earthquake as: 524+ = 10528+144Ms = x 10 each that in increase 10, of It times. amount same = 27.5? = more energy comes and body dramatically

Seismology to ways or body particular of a = m magnitude in displacement or (P selected for can factors 1945). Gutenberg, news in a is logigA = magnitude horizontal in distance magnitudes ~ m an by magnitude log;oE E = E means 27.5-fold factor a by 271 the produce (27.59/27.5° times of seismic the energy the earthquakes, increase moment magnitude:

Earthquake different whether amplitude wave of correcting Correction of magnitude Mg wave surface of amplitude epicentral wave released wave surface 27.54. This = a about increase approximately to 7.5 Fig. thousands half of all of 90% large to cease consider

are on the body ground period factor 35 p. Richter scale, popular amplitudes. wave Hou tl surface energy 10'“* amplitude earthquakes in are there than about 7.1). very to

”
7 There on = m = A = T = a Surface =<<a and The the to factor represents increase earthquake more 8); (Table For amplitudes useful
Chapter depending depends where: The P-wave on waves: Body mately The tude ground must 6 tude 8 although ones, = (Ms above is, more