When an earth­quake hits, up to eight per cent of a city's pop­u­la­tion can suf­fer fa­tal in­juries, a new re­port sug­gests.That's be­cause the mass ca­su­al­ties, lac­er­a­tions, bro­ken bones and crush­ing in­juries as­so­ci­at­ed with these nat­ur­al dis­as­ters oc­cur when bridges and roads may be im­pass­able and lo­cal and re­gion­al emer­gency med­ical care is dis­rupt­ed, ac­cord­ing to a group of Boston re­searchers who re­port their find­ings on Thurs­day in the Lancet.

Mil­lions of peo­ple live in ma­jor cities, such as New York, Los An­ge­les, Tokyo, Del­hi and Shang­hai, that are sit­u­at­ed on fault lines, the re­searchers not­ed.In the past decade, earth­quakes have caused more than 780,000 deaths, ac­cord­ing to the re­port. Many peo­ple died im­me­di­ate­ly, while oth­ers died from their in­juries in the hours and weeks that fol­lowed.Hours af­ter an earth­quake, a sec­ond wave of deaths oc­curs among vic­tims with se­ri­ous in­juries, such as liv­er or spleen lac­er­a­tions, bro­ken pelvis­es and head in­juries, the re­searchers re­vealed, and the fa­tal­i­ties don't stop there.

In the days and weeks fol­low­ing an earth­quake, more peo­ple with sep­sis (blood in­fec­tion) and mul­ti-or­gan fail­ure al­so die from their in­juries. Peo­ple with sep­sis are two and a half times more like­ly to die than those with­out it, the re­port re­vealed.More­over, earth­quake vic­tims with chron­ic dis­eases, like di­a­betes and heart dis­ease, are at greater risk of death due to lim­it­ed ac­cess to med­ical care.

Up to 15 per cent of a city's pop­u­la­tion could al­so be crushed by heavy loads, re­sult­ing in am­pu­ta­tions and kid­ney fail­ure, ac­cord­ing to the re­port. The death rate for peo­ple in kid­ney fail­ure in the wake of an earth­quake ranges from 14 per cent to 48 per cent, the re­searchers added.Still, they not­ed, the most com­mon earth­quake-re­lat­ed in­juries in­clude the fol­low­ing:

-Lac­er­a­tions (65 per cent)

-Bro­ken bones (22 per cent)

-Bruis­es or sprains (six per cent)

-Crush in­juries (three per cent to 20 per cent.)

Earth­quakes could al­so trig­ger heart at­tacks. The re­port re­vealed heart at­tacks rose by 35 per cent in the week fol­low­ing the 1994 earth­quake in North­ridge, Cal­i­for­nia Sim­i­lar surges were re­port­ed in oth­er places, such as Tai­wan. An in­crease in ar­rhyth­mias and cas­es of high blood pres­sure were al­so record­ed fol­low­ing this type of nat­ur­al dis­as­ter.

Earth­quakes can al­so harm the health of peo­ple who are dis­placed from their homes, ac­cord­ing to the re­port. Over­crowd­ed shel­ters can lead to epi­demics of in­fec­tious dis­eases. Bod­ies, how­ev­er, gen­er­al­ly do not play a ma­jor role in the spread of dis­ease, the re­searchers not­ed.

Men­tal health is­sues, par­tic­u­lar­ly de­pres­sion and post-trau­mat­ic stress dis­or­der, al­so in­crease in the wake of ma­jor earth­quakes.Chil­dren are of­ten at high­er risk of in­jury and death than are adults dur­ing earth­quakes, the re­searchers said. The el­der­ly are al­so more like­ly to be ad­verse­ly af­fect­ed, since they may not be able to re­spond as quick­ly or may be un­will­ing to evac­u­ate their homes.

Ac­cord­ing to the BBC, in the past decade, earth­quakes have caused more than 780,000 deaths-al­most 60 per cent of all dis­as­ter-re­lat­ed mor­tal­i­ty. Oth­er dis­as­ters, such as floods and hur­ri­canes typ­i­cal­ly cause many deaths from drown­ing, but few­er in­juries.It is es­ti­mat­ed that for every per­son killed in an earth­quake, three oth­ers are in­jured.De­pres­sion can al­so be com­mon af­ter earth­quakes af­fect­ing up to 72 per cent of the pop­u­la­tion.Fol­low­ing the 1999 Turkey earth­quake, stud­ies show that 17 per cent of the pop­u­la­tion had sui­ci­dal thoughts.