Intensity Scale.docx

Intensity Scale

Description

I

Scarcely Perceptible - Per Percep ceptib tible le to peo people ple und under er fav favora orabl ble e circumstances. Delicately balanced objects are disturbed slightly. Still Water in containers oscillates slowly.

II

Slightly Felt - Felt by few individuals at rest indoors. Hanging obje ob ject cts s sw swin ing g sl slig ight htly ly.. St Stil illl Wa Wate terr in cont contai aine ners rs os osci cill llat ates es noticeably.

III

Weak - Felt by many people indoors especially in upper floors of  buil bu ildi ding ngs. s. i ibr brat atio ion n is fe felt lt li li!e !e on one e pa pass ssin ing g of a li ligh ghtt tr truc uc!. !. Di""iness and nausea are e#perienced by some people. Hanging object obj ects s swi swing ng mod modera eratel tely. y. St Still ill wat water er in con contai tainer ners s osc oscill illate ates s moderately.

IV

Moderately Strong - Fel Feltt gen genera erally lly by peo people ple indoors indoors and by some people outdoors. $ight sleepers are awa!ened. ibration is felt fe lt li li!e !e a pa pass ssin ing g of he heav avy y tr truc uc!. !. Ha Hang ngin ing g ob obje ject ctss sswi wing ng considerably. Dinner% plates% glasses% windows and doors rattle. Floors and walls of wood framed buildings crea!. Standing motor  cars may roc! slightly. $i&uids in containers are slightly disturbed. Water Wa ter in con contai tainer ners s osc oscill illate ate str strong ongly ly.. 'um 'umbli bling ng sou sound nd may sometimes be heard.

V

Strong - (en (enera erally lly fel feltt by mos mostt peo people ple ind indoor oors s and out outdoo doors. rs. )any sleeping people are awa!ened. Some are frightened% some run outdoors. Strong sha!ing and roc!ing felt throughout building. Hanging objects swing violently. Dining utensils clatter and clin!* some are bro!en. Small% light and unstable objects may fall or  overtu ove rturn. rn. $i& $i&uid uids s spi spill ll fro from m fil filled led ope open n con contai tainer ners. s. Sta Standi nding ng vehicles roc! noticeably. Sha!ing of leaves and twigs of trees are noticeable.

VI

Very Strong - )any people are frightened* many run outdoors. Some people lose thei theirr balan balance. ce. motorists motorists feel li!e drivi driving ng in flat tires. Heavy objects or furniture move or may be shifted. Small church bells may ring. Wall plaster may crac!. ery old or poorly built bui lt hou houses ses and man man-ma -made de str struct ucture ures s are sli slight ghtly ly dam damage aged d though well-built structures are not affected. $imited roc!falls and roll ro llin ing g bo boul ulde ders rs oc occu curr in hi hill lly y to mo moun unta tain inou ous s ar area eas s an and d escarpments. +rees +rees are noticeably sha!en.

VII

Destructive - )o )ost st pe peop ople le ar are e fr frig ight hten ened ed an and d ru run n ou outd tdoo oors rs.. People find it difficult to stand in upper floors. Heavy objects and furnit fur niture ure ove overtu rturn rn or top topple ple.. ,ig church church bel bells ls may ring. ld or  poorly-built structures suffer considerably damage. Some well-built structure stru ctures s are slightly damaged. damaged. Some crac!s may appear on di!es% fish ponds% road surface% or concrete hollow bloc! walls. $imi $i mite ted d li li&u &uef efac acti tion on%% la late tera rall sp spre read adin ing g an and d la land ndsl slid ides es ar are e

observed. +rees are sha!en strongly. $i&uefaction is a process by which loose saturated sand lose strength during an earth&ua!e and behave li!e li&uid/.

VIII

Very Destructive - People panic!y. People find it difficult to stand even outdoors. )any well-built buildings are considerably damaged. 0oncrete di!es and foundation of bridges are destroyed by ground settling or toppling. 'ailway trac!s are bent or bro!en. +ombstones may be displaced% twisted or overturned. 1tility posts% towers and monuments mat tilt or topple. Water and sewer pipes may be bent% twisted or bro!en. $i&uefaction and lateral spreading cause man- made structure to sin!% tilt or topple. 2umerous landslides and roc!falls occur in mountainous and hilly areas. ,oulders are thrown out from their positions particularly near the epicenter. Fissures and faults rapture may be observed. +rees are violently sha!en. Water splash or stop over di!es or ban!s of  rivers.

IX

Devastating - People are forcibly thrown to ground. )any cry and sha!e with fear. )ost buildings are totally damaged. bridges and elevated concrete structures are toppled or destroyed. 2umerous utility posts% towers and monument are tilted% toppled or bro!en. Water sewer pipes are bent% twisted or bro!en. $andslides and li&uefaction with lateral spreadings and sandboils are widespread. the ground is distorted into undulations. +rees are sha!en very violently with some toppled or bro!en. ,oulders are commonly thrown out. 'iver water splashes violently on slops over di!es and ban!s.

X

Completely Devastating - Practically all man-made structures are destroyed. )assive landslides and li&uefaction% large scale subsidence and uplifting of land forms and many ground fissures are observed. 0hanges in river courses and destructive seiches in large la!es occur. )any trees are toppled% bro!en and uprooted

Many objects fell from store shelves; many homes sustained minor damage; pictures fell; a few windows cracked; small appliances moved.

Anaheim : A scoreboard structure at Anaheim stadium collapsed and damaged over 1000 seats. A few windows cracked; a few small objects overturned; a few people ran out of buildings. elt by almost all people; many awakened. !anging pictures swayed. "rees and bushes shook slightly to moderately. #urbank : $olice reported that the southwest section of town su%ered the worst damage& including damage to the airport and the power plant. Masonry walls were destroyed and underground pipes broken. Many windows were broken out; light and heavy furniture was overturned. Many chimneys fell. 'hatsworth : Masonry fences were destroyed; underground pipes were put out of service; sidewalks and roadways sustained large cracks; many chimneys were broken at the roo(ine or fell. A beverage)can plant sustained e*tensive damage to manufacturing e+uipment and had to cease operations for an estimated ten weeks. ,ne person was killed by falling objects in his house. 'ompton : $laster walls sustained hairline cracks and separated from ceiling or (oor; a few chimneys were cracked; several small items were overturned; several items fell from store shelves; water splashed onto sides of swimming pools.  -owntown os Angeles : "he roof partially collapsed in the 'ity !all parking structure& and water lines broke in 'ity !all and in $arker 'enter. /nterior and e*terior walls sustained large cracks; some windows were broken out; a few small objects overturned and fell. illmore : "he pictures+ue old part of town& which contained many brick buildings built early this century& su%ered e*tensive damage; some wood)frame houses were shifted o% their foundations. atural gas from a damaged pipeline ignited& and the re spread to a nearby mobile home park.  2*ercise 3 ) 34 ) 5lendale : /n the 5lendale 5alleria shopping mall& storefront windows were broken& ceilings and walls were cracked& and shops sustained water damage. A si*)story& unreinforced masonry building near the city hall sustained cracks in bearing walls. 6uestionnaire respondents reported that many glassware items and dishes broke& furniture and appliances were displaced& and shaking was felt in moving vehicles.  !ollywood : 7nreinforced masonry buildings were substantially damaged& including cracks in walls and collapse of upper walls and corners. 8ome wood)frame apartments shifted on their foundations. A few tombstones shifted; some roads were cracked; and many chimneys were broken at the roof line. ong #each : A few small objects overturned; felt by almost all people; many people awakened. !anging pictures swayed or fell. "rees and bushes shook slightly to moderately. Malibu : At the 9. $aul 5etty Museum& e+uipment designed to protect against earth+uake damage worked e%ectively& although several artifacts in transit from storage to display were damaged. 'racks reported in walls& chimneys& and windows; a few items shaken o% store shelves.

 Monrovia : 8everal chimneys were cracked or twisted; cracks in plaster walls& masonry fences& and windows; several small objects such as dishes fell and were broken; cars rocked moderately. orthridge : 8evere damage at the orthridge ashion Mall& including partial collapse at #ullocks department store and partial to near)complete collapse of three parking structures. Many wood)frame apartment comple*es were destroyed& including the orthridge Meadows comple* in which 1 people died. "he 'alifornia 8tate 7niversity at orthridge sustained <=0 million in damage& including the collapse of a new concrete parking structure and structural damage to the steel) frame ,viatt ibrary. A 8outhern $acic freight train derailed in orthridge& spilling >000 gallons of sulfuric acid and 3000 gallons of diesel fuel. ,*nard : /nterior walls sustained a few large cracks; a few chimneys and windows cracked; several small objects overturned; light and heavy furniture and appliances were displaced; a few people ran out of buildings; moving vehicles rocked moderately. $almdale : Masonry fences& sidewalks& a few chimneys& a few windows& and stucco and plaster walls cracked. A few items were shaken o% store shelves; a few people ran outdoors. "he ?incent electric power substation was signicantly damaged. $iru : At the historic $iru mansion& chimneys fell& a porch pillar was jarred loose& and several statues fell and were broken. 2lsewhere& masonry fences were partially damaged; streets and interior walls were cracked; light furniture and small appliances were overturned; and heavy furniture and appliances were displaced. @edondo  #each : "he ings !arbor Marina sustained damage due to subsidence of ll. $laster walls sustained hairline cracks; a few small objects overturned and fell; water splashed onto sides of pools.  @osemead : A few tombstones fell; several small objects overturned and fell.  8anta 'larita : "he 8anta 'larita 'ity !all su%ered an estimated 3 million in damage; the 'alifornia /nstitute of the Arts sustained an estimated =0 million in damage; severe damage to some steel)frame buildings. 8and boils were observed at several locations. 8an ernando : According to preliminary estimates& 3=B of concrete tilt)up buildings had serious structural damage& including partial collapse. Minor ground cracking occurred. A reinforced)masonry building under construction sustained signicant damage. Magnitude and /ntensity ) <0 C  8anta Monica : Masonry fences were destroyed; undergrounds pipes were put out of service; sidewalks and roads sustained large cracks; many chimneys had bricks fall or were broken at the roof line. 8anta $aula : "hirteen commercial buildings were damaged to the e*tent that they were DyellowtaggedE Faccess limited until repairs

could be madeG. 8haking was felt by andHor awakened most to all people; people had diIculty walking or standing. 8herman ,aks : 1= buildings were seriously damaged& including bad cracking of reinforced concrete columns in the @adisson !otel& shear failures at the our 8easons building& and severe damage and partial collapse of si* concrete parking structures. "here also was e*tensive damage to wood)frame structures& including collapse of 1J structures on stilts. 8ome ground cracking was reported. 8imi ?alley : /n some residential areas& reinforced chimneys and (oor slabs were damaged& interiors and building contents were severely damaged& and some people were thrown from their beds. 8idewalks and roads sustained large displacements or buckled& and masonry fences and underground pipes were destroyed. 8and boils were reported& and ground spreading was widespread.  "arKana : #usinesses along ?entura #oulevard sustained an estimated 3.1 million in damage& mostly due to broken windows and damaged inventory. /n the residential district& chimneys were damaged or destroyed in some areas& although houses in other areas sustained no damage visible from the outside. Masonry fences were destroyed; underground pipes were put out of service; sidewalks and roads cracked or buckled.  "housand ,aks : 8everal homes sustained damage& most of which consisted of cracks in interior walls& although there were isolated locations of stronger damage. Masonry fences and walls partially fell; some windows were broken out; many small objects overturned and fell; light furniture and small appliances were displaced; standing vehicles rocked moderately; moving vehicles slightly.  "opanga : Masonry fences partially fell; underground pipes cracked; cracks in walls& chimneys& and windows. 8everal dishes and knickknacks were broken. ight furniture and small appliances were displaced. A few people ran out of buildings.  "ujunga : Masonry fences partially fell; underground pipes were cracked; walls sustained hairline cracks; several small objects overturned; several dishes and knickknacks were broken; light furniture was displaced; felt strongly in standing and moving vehicles.  Lhittier : Many objects fell from shelves; many homes sustained minor damage. ,ther sites : A number of sites in the area covered by igure 3.J reported Mercalli intensity ? shaking. 8ome of these sites are indicated on the gure.