Mmiri naeme ka ala bụrụ mmiri

Mmiri na-eme mgbe ala naenweghị njikọ ma ọ bụ ala na-adịghị mma naefunahụ ike na nkwụsi ike na nzaghachi maka nrụgide a naetinye dịka ịma jijiji noge ala ọma jijiji ma ọ bụ mgbanwe mberede ọzọ na ọnọdụ nrụgide, nke ihe naabụkarị ihe siri ike na-akpa àgwà dị ka mmiri. Na imepụta ala, Allen Hazen ji okwu ahụ bụ "liquefied" mee ihe na mbụ naezo aka na ọdịda nke Calaveras Dam na California na 1918. Ọ kọwara usoro nke mmiri na-asọba n'ụgbọ mmiri ahụ dị ka:

A naahụkarị ihe omume a nala ájá jupụtara, nke naenweghị isi (nke dị ala ma ọ bụ nke naadịghị mkpirikpi). Nke a bụ nihi na ájá naenweghị isi nwere ọchịchọ ịtachi mgbe a naetinye ibu. Ájá siri ike, nụzọ dị iche, naagbasawanye nọnụ ọgụgụ ma ọ bụ 'gbasawanye'. Ọ bụrụ na mmiri jupụtara nala, ọnọdụ nke naadịkarị mgbe ala dị nokpuru tebụl mmiri ma ọ bụ ọkwa oké osimiri, mgbe ahụ mmiri naejupụta oghere dị netiti mkpụrụ ala ('oghere oghere'). Nịzaghachi mkpakọ ala, nrụgide mmiri na-abawanye na mmiri na-anwa isi nala naaga nebe nrụgide dị ala (na-emekarị nelu ala). Otú ọ dị, ọ bụrụ na a naetinye loading ngwa ngwa ma buru ibu, ma ọ bụ na-ekwughachi ọtụtụ ugboro (dịka ala ọma jijiji, loading ebili mmiri) nke mere na mmiri anaghị apụ tupu a naeji usoro ọzọ nke loading, nrụgide mmiri nwere ike iwulite ruo nókè ọ gafere ike (mmetụta) netiti mkpụrụ nke ala nke naeme ka ha na-emetụtụrụ. Njikọ ndị a netiti ọka bụ ụzọ e si ebufe ibu sitere na ụlọ na ala dị nelu site nelu ala gaa na ala ma ọ bụ nkume dị omimi. Mfu a nke ọdịdị ala naeme ka ọ ghara inwe ike (ikike ịnyefe nrụgide shear), a pụkwara ịhụ na ọ naaga dị ka mmiri (ya mere 'liquefaction').

Ọ bụ ezie na a ghọtala mmetụta nke mmiri ara ehi, ndị injinia chọpụtara na ala ọma jijiji nke 1964 na ala ọmaga nke Niigata. Ọ bụ isi ihe kpatara mbibi e mere na San Francisco's Marina District noge ala ọma jijiji Loma Prieta nke afọ 1989, na nọdụ ụgbọ mmiri Kobe noge nnukwu ala ọma jijijii Hanshin nke afọ 1995. N'oge na-adịbeghị anya, mmiri na-agbapụta nala bụ ihe kpatara nnukwu mmebi nke ụlọ obibi na mpaghara ndị dị n'ebe ọwụwa anyanwụ na obodo ndị dị na Christchurch noge ala ọma jijiji nke Canterbury na 2010 ọzọ naesote ala ọma jijizi Christchurch nke sochiri na mbido na etiti afọ 2011. Nabalị iri abụọ na asatọ nọnwa Septemba nafọ 2018, ala ọma jijiji nke ruru 7.5 mere na mpaghara Central Sulawesi nke Indonesia. Mmiri naesi nala apụta kpuchiri ógbè Balaroa na Petobo dị mita 3 (9.8 ) nime apịtị. Gọọmentị Indonesia naatụle ịkọwa mpaghara abụọ nke Balaroa na Petobo, nke e liri kpamkpam n'okpuru apịtị, dị ka ili ọha.

Usoro iwu ụlọ nọtụtụ mba chọrọ ka ndị injinia tụlee mmetụta nke mmiri naagbapụta nala na imewe ụlọ ọhụrụ na akụrụngwa dị ka àkwà mmiri, ihe mgbochi mmiri na ihe owuwu naejigide.

 Nkọwa teknụzụ 
Mmiri naeme ka ala dị mmiri mgbe nrụgide dị irè (ike ịcha) nke ala belatara ruo nụzọ bụ isi efu. Nke a nwere ike ịmalite site na ma ọ bụ monotonic loading (ya bụ, otu, mberede nke mgbanwe na nrụgide - ihe atụ gụnyere mmụba nke ibu na embankment ma ọ bụ ọnwụ mberede nke nkwado mkpịsị ụkwụ) ma ọ bụ cyclic loading (i.e. mgbanwe ugboro ugboro na ọnọdụ nrụgide - Ihe atụ gụnyere loading ebili mmiri ma ọ bụ ala ọma jijiji). Nọnọdụ abụọ ahụ, ala dị nọnọdụ naenweghị isi, na nke nwere ike ịmepụta nrụgide mmiri dị ukwuu na mgbanwe nke ibu bụ nke kachasị nwee ike ịghọ mmiri. Nke a bụ nihi na ala naenweghị isi nwere ọchịchọ ịtachi mgbe a naakpụ ya, naemepụta nnukwu nrụgide mmiri dị n'ime ka a naebufe ibu site na ọkpụkpụ ala gaa na mmiri dị n"akụkụ ya noge a naetinye ya. Ka nrụgide mmiri naarị elu, mbelata nke ike nke ala naeme ka nrụgide dị irè belata.
Liquefaction nwere ike ime na ájá ma ọ bụ ala naabụghị plastik, mana ọ nwere ike ime n'ọnọdụ ndị a naadịghị ahụkebe na gravels na ụrọ (lee ụrọ ngwa ngwa).

'Ọdịda nke mmiri' nwere ike ịmalite ma ọ bụrụ na ike nke ala belata nokpuru nrụgide achọrọ iji nọgide naenwe nguzozi nke ndagwurugwu ma ọ bụ ntọala nke ihe owuwu. Nke a nwere ike ime nihi loading monotonic ma ọ bụ loading cyclic, ọ pụkwara ịbụ na mberede na ọdachi. Ihe atụ akụkọ ihe mere eme bụ ọdachi Aberfan. Casagrande zoro aka nụdị ihe omume a dị ka 'mmiri na-agbapụta' ọ bụ ezie na a chọghị ọnọdụ nke nrụgide efu maka nke a.

'Cyclic liquefaction' bụ ọnọdụ ala mgbe nnukwu ụdị shear gbakọtara na nzaghachi maka loading cyclic. Ụdị ntụle maka ihe atụ nke nrụgide efu naarụ ọrụ bụ 5% okpukpu abụọ nke shear strain. Nke a bụ nkọwa nke ala, nke a naemekarị site na cyclic triaxial, cyclic direct simple shear, ma ọ bụ cyclic torsional shear type apparatus. A naeme nnwale ndị a iji chọpụta nguzogide ala na liquefaction site nịhụ ọnụ ọgụgụ nke okirikiri nke loading na otu oke nrụgide achọrọ iji mee ka 'ọdịda'. A naakọwa ọdịda ebe a site na njirimara shear strain a kpọtụrụ aha nelu.

Okwu 'cyclic mobility' naezo aka na usoro nke mbelata naaga n'ihu nke nrụgide dị irè nihi loading cyclic. Nke a nwere ike ime nụdị ala niile gụnyere ala siri ike. Otú ọ dị, mgbe ị ruru ọnọdụ nke enweghị nrụgide dị irè, ala ndị dị otú ahụ naagbasa ozugbo ma nwetaghachi ike. Nihi ya, ụdị shear dị obere karịa ezigbo ọnọdụ nke mmiri ara.

 Ihe mere 
Liquefaction nwere ike ime nala ndị naenweghị mmiri na ala ndị naadịghị mma, dị ka ájá ma ọ bụ ájá na gravels nwere mmiri naadịghị. N'oge ebili mmiri, naabụkarị cyclic undrained loading, dịka seismic loading, ájá naagbadata na olu, nke naemepụta mmụba na nrụgide mmiri ha na ya mere mbelata na ike shear, ya bụ mbelata na nrụgide dị irè.

Ihe ndị naenwekarị ike ịba mmiri bụ ihe naeto eto (Holocene-age, nke a naetinye nime afọ 10,000 gara aga) ájá na silts nke nha ọka yiri ya (nke a haziri nke ọma), nàkwà dịkarịa ala mita n'ịdị arọ, ma jupụta na mmiri. A naahụkarị ihe ndị dị otú ahụ nakụkụ osimiri, osimiri, dunes, na ebe ikuku naebugharị (loess) na ájá gbakọtara. Ihe atụ nke mmiri naagbapụta nala gụnyere ájá naagbagharị agbagharị, ụrọ naagba ọsọ, mmiri naadịghị mma na mmiri naeme ka ala ọma jijiji kpatara.

Dabere na ọnụ ọgụgụ mbụ nke oghere, ihe ala nwere ike imeghachi omume na loading ma ọ bụ strain-softing ma ọ bụ stress-hardening. Ala dị nro, dịka ájá naenweghị isi, nwere ike ime ka ọ daa, ma ọ bụ notu ma ọ bụ naagagharị agagharị, ma ọ bụrụ na nrụgide naakpụ akpụ dị ukwuu karịa ike kachasị elu ma ọ bụ nke naakwụsị akpụ nke ala. Nọnọdụ a, mmiri naagbapụta naeme, ebe ala naemebi na nrụgide dị ala naadịgide adịgide. Ọ bụrụ na ala ahụ siri ike, dịka ọmụmaatụ, ọ gaabụrịrị na ọ gaadịkwu arọ, ọ gaghị abụ mmiri naasọ asọ. Otú ọ dị, ịdị nro nke cyclic nwere ike ime nihi ibu naenweghị mmiri ozuzo, dịka ibu ala ọma jijiji. Mgbagwoju anya noge cyclic loading naadabere na njupụta nke ala, oke na ogologo oge nke cyclic loading, na ọnụọgụ nke ntụgharị nrụgide shear. Ọ bụrụ na nrụgide gbanwee, nrụgide shear dị irè nwere ike iru efu, naenye ohere ka cyclic liquefaction mee. Ọ bụrụ na nrụgide anaghị eme, nrụgide efu enweghị ike ime, naagagharị naaga nihu.Robertson, P.K., and Fear, C.E. (1995). "Liquefaction of sands and its evaluation.", Proceedings of the 1st International Conference on Earthquake Geotechnical Engineering, Tokyo

Nnọgide nke ala naenweghị njikọ gaadabere na njupụta nke ala, nrụgide mgbochi, ọdịdị ala (uwe, afọ na simenti), ịdị ukwuu na ogologo oge nke ibugharị cyclic, na ókè nrụgide shear naeme.

 Ikike ime ka mmiri dị nro: nyocha nyocha nke ihe omimi dị mfe 
A chọrọ akụkụ atọ iji nyochaa ikike liquefaction site na iji usoro nyocha dị mfe:

 Ihe omuma nke ihe na-eguzogide mmiri: Standard Penetration Resistance (SPT), Cone Penetration resistance (CPT), ma ọ bụ shear wave velocity (Vs) [Cetin, K.O., Seed, R.B., Armen Der Kiureghian, M., Tokimatsu, K., Harder, L.F. Jr., Kayen, R.E., Moss, R.E.S. (2004) SPT-Based Probabilistic and Deterministic Assessment of Seismic Soil Liquefaction Potential, Journal of Geotechnical and Geoenvironmental Engineering, American Society of Civil Engineers, Journal of Geotechnical and Geoenvironmental Engineering, Vol. 130, No. 12, December 2004, pp. 1314-1340. http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282004%29130%3A12%281314%29 ]  [I.M. Idriss, Ross W. Boulanger, 2nd Ishihara Lecture: SPT- and CPT-based relationships for the residual shear strength of liquefied soils, Soil Dynamics and Earthquake Engineering, Volume 68, 2015, Pages 57 68, ISSN 0267-7261, https://doi.org/10.1016/j.soildyn.2014.09.010.]  [Robb E.S. Moss, Raymond B. Seed, Robert E. Kayen, Jonathan P. Stewart, Armen Der Kiureghian, and K. Onder Cetin (2006) "CPT-Based Probabilistic and Deterministic Assessment of In Situ Seismic Soil Liquefaction Potential" Journal of Geotechnical and Geoenvironmental Engineering 132(8) 1032-1051. http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282006%29132%3A8%281032%29]  [Kayen, R., Moss, R., Thompson, E., Seed, R., Cetin, K., Kiureghian, A., Tanaka, Y., and Tokimatsu, K. (2013). ”Shear-Wave Velocity–Based Probabilistic and Deterministic Assessment of Seismic Soil Liquefaction Potential.” J. Geotech. Geoenviron. Eng., 139(3), 407–419. http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0000743 ] 
 Ibu nke ala ọma jijiji, nke a tụrụ dị ka ọnụọgụ nrụgide cyclicEvaluation of soil liquefaction from surface analysis   
 ikike nke ala iji guzogide liquefaction, gosipụtara na usoro nke cyclic resistance ratio (CRR)

 Mmiri nke ala ọma jijiji 
áká_ịkẹngạ|thumb|Ájá na-agbaze noge ala ọma jijiji Christchurch nke afọ 2011.
Mmetụta ndị a naemepụta noge nnukwu ala ọma jijiji nwere ike ịmanye mmiri dị nokpuru ala na ájá naagbapụta nelu ala. Enwere ike ịhụ nke a nelu ala dị ka mmetụta ndị a maara nụzọ ọzọ dị ka "ájá na-esi ísì ụtọ", "ájá" ma ọ bụ "ájá ọkụ". Enwere ike ịkọwa nkwarụ ala ọma jijiji dị otú ahụ dị ka nkwarụ isi ma ọ bụrụ na ọ dị na ma ọ bụ nso na mmebi ahụ gbawara agbawa, ma ọ bụ nkwarụ a naekesa ma ọ bụrụhaala na ọ dị anya site na mmebi nke gbawara aghara.
áká_èkpè|thumb|Map nke naemetụta mmiri  ihe si na map USGS maka San Francisco Bay Area. Ọtụtụ ebe nchegbu na mpaghara a naenwekwa ọtụtụ obodo mepere emepe.
Ihe ọzọ a naahụkarị bụ ala naagbanwe agbanwe - ịgbaji na ịkwagharị nke ala na ndagwurugwu ma ọ bụ gaa nakụkụ osimiri, iyi, ma ọ bụ ụsọ mmiri naenweghị nkwado. A naakpọ ọdịda nke ala nụzọ a 'ịgbasa nakụkụ', ọ pụkwara ime na ndagwurugwu naadịghị omimi na nkuku naanị 1 ma ọ bụ 2 degrees site na horizontal.

Otu akụkụ dị mma nke mmiri naagbapụta nala bụ omume maka mmetụta nke ala ọma jijiji ka a naebelata ya nke ukwuu (ebelata) maka ihe fọdụrụ na ala ọma jijijii ahụ. Nke a bụ nihi na mmiri anaghị akwado nrụgide shear yabụ ozugbo ala naaghọ mmiri nihi ịma jijiji, ala ọma jijiji naesote (nke ebili mmiri naebufe nala) anaghị ebufe n'ụlọ dị n'elu ala.

Nnyocha nke ihe ndị dị na mmiri nke ala ọma jijiji tupu akụkọ ihe mere eme hapụrụ, nke a naakpọ paleoliquefaction ma ọ bụ paleoseismology, nwere ike ikpughe ozi gbasara ala ọma jijijuputa nke mere tupu edebe ndekọ ma ọ bụ enwere ike ịtụle ya nụzọ ziri ezi.

Mmiri nke ala naakpata site na ala ọma jijiji bụ isi ihe naenye aka nihe ize ndụ nke ala ọma jijijii nobodo ukwu.

 Mmetụta 
áká_ịkẹngạ|thumb|Mmebi na Brooklands site na ala ọma jijiji nke Canterbury na 2010, ebe ihe naese nelu mmiri nke mmiri naeme ka ọrụ dị nokpuru ala gụnyere olulu mmiri a.
Mmetụta nke mmiri naagbapụta nala na gburugburu ebe obibi nwere ike imebi ihe nke ukwuu. Ụlọ ndị ntọala ha naebute kpọmkwem nelu ájá nke naeme ka ọ bụrụ mmiri gaenwe nkwado na mberede, nke gaeme ka ụlọ ahụ nwee nkwụsịtụ siri ike na nke naadịghị mma naakpata mmebi ihe owuwu, gụnyere ịgbaji nke ntọala na mmebi nke ụlọ ahụ, ma ọ bụ hapụ ihe owuwu ahụ naenweghị ike ịrụ ọrụ, ọbụlagodi na enweghị mmebi ihe. Ebe a naenwe obere ala naenweghị mmiri netiti ntọala ụlọ na ala mmiri, ụdị ntọala 'naagbaji' nwere ike ime. Ebe obibi naezighị ezi nwere ike imebi ụzọ ọrụ nokpuru ala. Mmetụta naarịgo elu nke mmegharị nke ala mmiri naagafe nime mkpo nwere ike ịgbaji ntọala ntọala naadịghị ike ma banye nụlọ site na ọwa ọrụ, ma nwee ike ikwe ka mmiri mebie ihe dị n'ime ụlọ na ọrụ eletrik.

Àkwà mmiri na nnukwu ụlọ ndị e wuru na ntọala nwere ike ịhapụ nkwado site na ala dị nakụkụ ya na eriri, ma ọ bụ naezu ike na ntụgharị.

Ịgbanye ala na ala nakụkụ osimiri na ọdọ mmiri nwere ike ịdọrọ nelu ala mmiri (nke a naakpọ 'ịgbasa nakụkụ'), naemeghe nnukwu oghere ala, ma nwee ike imebi ụlọ, àkwà mmiri, okporo ụzọ na ọrụ dịka mmiri, gas sitere nokike, nsị, ike na nkwukọrịta arụnyere nala ahụ metụtara. Tanki na oghere ndị e liri nala nwere ike ịba nelu mmiri nala mmiri nihi na ọ naese nelu. Ihe mgbochi ala dị ka ihe mgbochi mmiri na ihe mgbochi ala nwere ike ịhapụ nkwụsi ike ma ọ bụ daa ma ọ bụrụ na ihe mejupụtara ihe mgbochi ma ọ bụ ntọala ya naeme ka mmiri dị.

Ka oge naaga, mmiri nke ihe ndị dị nala nihi ala ọma jijiji nwere ike inye ihe nne na nna siri ike nke fragipan nwere ike ịmalite site na pedogenesis.

 Ụzọ e si egbochi ya 

Ndị injinia ala ọma jijiji chepụtara usoro mgbochi ma gụnye usoro dị iche iche nke mkpakọ ala dị ka mkpakọ nke ala (mkpakọ dị nala site na vibrators miri emi), mkpakọ siri ike, na ogidi nkume vibro. Ụzọ ndị a naeme ka ala sie ike ma mee ka ụlọ zere mmiri naagbapụta nala.

Enwere ike ibelata ụlọ ndị dị ugbu a site na itinye ahịhịa nime ala iji mee ka ala nke naeme ka ọ kwụsie ike. Usoro ọzọ a naakpọ IPS (Induced Partial Saturation) bụ ihe gaekwe omume ugbu a itinye nọrụ n'ọ̀tụ̀tụ̀ buru ibu. Nime usoro a, a naebelata ogo saturation nke ala.

 Ájá naagbagharị agbagharị 
A naemepụta ájá naagbagharị agbagharị mgbe mmiri naejupụta nebe ájá na ájá naelu. Mgbe mmiri tọrọ nime ájá ahụ enweghị ike ịpụ, ọ naemepụta ala mmiri nke naenweghị ike iguzogide ike. A naemepụta ájá naagbagharị site na iguzo ma ọ bụ (nelu) mmiri naasọ nokpuru ala (dị ka isi iyi dị nokpuru), ma ọ bụ site na ala ọma jijiji. Nihe banyere mmiri naasọ nokpuru ala, ike nke mmiri naaga naemegide ike ndọda, naeme ka granules nke ájá dịkwuo elu. Nihe banyere ala ọma jijiji, ike ịma jijiji nwere ike ịbawanye nrụgide nke mmiri naadịghị omimi, ájá naeme ka mmiri dị nro na ihe ndị dị nime ala. Nọnọdụ abụọ ahụ, elu mmiri ahụ naefunahụ ike, naeme ka ụlọ ma ọ bụ ihe ndị ọzọ dị nelu ahụ mikpuo ma ọ bụ daa.

Mmiri ahụ nwere ike iyi ihe siri ike ruo mgbe mgbanwe nke nrụgide ma ọ bụ ihe mgbagwoju anya naamalite liquefaction, naeme ka ájá mepụta nkwụsịtụ na ọka ọ bụla gbara obere film nke mmiri gburugburu. Nchịkọta a naenye ájá naagbagharị agbagharị, na ihe ndị ọzọ naagbapụta, ọdịdị dị ka mmiri. Ihe ndị dị nime ájá naadaba na ọkwa nke ịdị arọ nke ihe ahụ hà ka ịdị arọ ya na ngwakọta ájá / mmiri na ihe ahụ naese nelu mmiri nihi ịdị arọ.

 Ọkpụkpụ ụrọ ngwa ngwa 

Ọkpụkpụ ụrọ, nke a maara dị ka Leda Clay na Canada, bụ gel jupụtara na mmiri, nke nụdị ya siri ike yiri ụrọ dị oke egwu. Ọkpụkpụ a nwere ọchịchọ ịgbanwe site na ọnọdụ siri ike gaa na mmiri mgbe a naenye ya nsogbu. Mgbanwe a naaga nihu nihu site na ihe siri ike gaa na mmiri bụ usoro a maara dị ka liquefaction spontaneous. Ọkpụkpụ ahụ naejigide ihe siri ike nagbanyeghị nnukwu mmiri dị na ya (ruo 80% site na olu), nihi na nrụgide elu naejide ụrọ naekpuchi mmiri. Mgbe ihe owuwu ahụ mebiri site na mgbagwoju anya ma ọ bụ shear zuru oke, ọ naabanye n'ọnọdụ mmiri.

A naahụ ụrọ ngwa ngwa naanị na mba ndị dị nebe ugwu dị ka Russia, Canada, Alaska na US, Norway, Sweden na Finland, nke glaciated noge Pleistocene.

Ọkpụkpụ ụrọ ngwa ngwa abụwo ihe kpatara ọtụtụ mbuze ala naegbu egbu. Na Canada naanị, a naejikọta ya na ihe karịrị 250 map landslides. Ụfọdụ nime ndị a bụ oge ochie, ọ pụkwara ịbụ ala ọma jijiji kpatara ya.

 Mmiri naadịghị mma 

Mmiri naagbada nokpuru mmiri bụ mmiri naadịghị mma ma nwee mmiri naagbadata na ndagwurugwu. Otu ihe atụ mere noge ala ọma jijiji Grand Banks nke 1929 nke kụrụ ugwu dị nụsọ oké osimiri nke Newfoundland. Minit ole na ole ka e mesịrị, eriri ekwentị ndị gafere Atlantic malitere ịgbaji nusoro, nebe dị anya na nebe naagbadata, nèzí ebe ala ahụ. A gbajiri eriri iri na abụọ na ngụkọta nke ebe iri abụọ na asatọ. E dekọrọ oge na ebe ziri ezi maka ezumike ọ bụla. Ndị naeme nchọpụta tụrụ aro na mmiri naagbada nokpuru mmiri nke dị kilomita 60 notu awa (100 km / h) ma ọ bụ mmiri naadịghị mma nke mmiri jupụtara na mmiri na ya gburu kilomita 400 (600 km) gbadaa na ndagwurugwu kọntinent site na etiti ala ọma jijiji ahụ, naagbanye eriri ka ọ na-aafe.

 Hụkwa 

 Ókè Atterberg
 Ájá kpọrọ nkụ
 Mmiri na-asọba
 Injinia ala ọma jijiji
 Fluidization
 Mmiri na-agbapụta
 Ugwu apịtị na-agbọpụta ọkụ
 Ubi Ubi
 Network for Earthquake Engineering Simulation#Soil liquefaction research
 Paleoseismology
 Ebe ájá na-esi ísì
 Nkwado
 Ọrịa na-emetụta ụkwara

 Ihe odide 

 Ịgụ ihe ọzọ 

 Seed et al., Ọganihu ndị na-adịbeghị anya na Injinia Liquefaction nke Ala: A Unified and Consistent Framework, 26th Annual ASCE Los Angeles Geotechnical Spring Seminar, Long Beach, California, Eprel 30, 2003, Earthquake Engineering Research Center
Òtù:Pages with unreviewed translations