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Astazi in istoria seismica globala

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  • #46
    17 octombrie 1989: cutremurul de la Loma Prieta, care a afectat San Francisco. A fost cel mai puternic cutremur produs in zona San Francisco dupa marele cutremur din 1906, desi nu se compara cu acesta din urma: 1906 Mw 7,7-7,8; 1989 Mw 6,9.

    https://en.wikipedia.org/wiki/1989_L...eta_earthquake

    Cutremurul a provocat pagube importante in regiunea San Francisco, inclusiv prin producerea unor fenomene de lichefiere. Doua pre-socuri moderate (ML 5,3 si 5,4) se produsesera in iunie 1988 si august 1989.

    The 1989 Loma Prieta earthquake occurred on California’s Central Coast on October 17 at 5:04 p.m. local time (1989-10-18 00:04 UTC). The shock was centered in The Forest of Nisene Marks State Park approximately 10 mi (16 km) northeast of Santa Cruz on a section of the San Andreas Fault System and was named for the nearby Loma Prieta Peak in the Santa Cruz Mountains. With an Mw magnitude of 6.9[10] and a maximum Modified Mercalli intensity of IX (Violent), the shock was responsible for 63 deaths and 3,757 injuries. The Loma Prieta segment of the San Andreas Fault System had been relatively inactive since the 1906 San Francisco earthquake (to the degree that it was designated a seismic gap) until two moderate foreshocks occurred in June 1988 and again in August 1989.

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    • #47
      21 octombrie 1868: cutremur puternic pe falia Hayward, langa San Francisco (Mw 6,7).Desi mai putin cunoscut si cu originea pe alta falie decat San Andreas, cutremurul a afectat serios San Francisco. Falia este considerata o potentiala amenintare ca sursa pentru un viitor cutremur semnificativ in zona San Francisco.

      Description:
      The 1868 Hayward earthquake occurred in the San Francisco Bay Area, California, United States on October 21. With an estimated moment magnitude of 6.3–6.7 and a maximum Mercalli intensity of IX (Violent), it was the most recent large earthquake to occur on the Hayward Fault Zone. It caused significant damage and a number of deaths throughout the region, and was known as the "Great San Francisco earthquake" prior to the 1906 San Francisco earthquake and fire.

      The earthquake occurred at 7:53 a.m. on October 21, 1868. Its epicenter was likely located near Hayward, California, and its magnitude has been estimated to have been 6.3–6.7 on the moment magnitude scale. At the surface, ground rupture was traced for 20 miles (32 km), from San Leandro to what is now the Warm Springs District in Fremont.

      The town of Hayward experienced the most damage, with nearly every building destroyed or significantly damaged in the earthquake. The Alameda County Courthouse in San Leandro was destroyed, which resulted in the re-location of the County Seat to Oakland, its current site. The adobe chapel of Mission San José in what is now Fremont was also destroyed, as were several buildings in San Jose, San Francisco and throughout Alameda County. Damage was reported from Santa Rosa in the north to Gilroy and Santa Cruz in the south. Thirty deaths were attributed to the earthquake.

      https://en.wikipedia.org/wiki/1868_Hayward_earthquake

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      • #48
        30 octombrie 1983: cutremurul de la Erzurum, Estul Turciei (Mw 6,9). Acest cutremur a precedat cutremurul vrancean din 1986, ceea ce arata ca Vrancea nu misca serios decat in anumite contexte seismice globale si regionale particulare (asa cum, de exemplu, seismul din 1908 a fost precedat de un cutremur pe falia Est-Anatoliana in 1905, iar cel din 1868 a fost de asemenea precedat de un cutremur pe EAF in 1866). Tot in 1983 s-au inregistrat cutremure puternice in Oceanul Indian-Asia: 18 aprilie zona de subductie Makran Mw 6,7; 30 noiembrie zona arhipelagului Chagos Mw 7,6; 31 decembrie Hindu Kush Mw 7,2. Astea sunt contextele sau ferestrele de timp in care se incadreaza si cutremurele vrancene mai semnificative. Vrancea nu misca la intamplare, oricand, in orice conditii, fara un context extern sugestiv.

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        • #49
          1 noiembrie 1755: megaseismul din Oceanul Atlantic, zona insulelor Azore, care a distrus Lisabona (incendii si tsunami). Cutremurul, cotat cu magnitudinea Mw 8,6-9,0, a fost resimtit pe o arie foarte larga in Vestul si centrul Europei, dar si in Nord-Vestul Africii.

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          • #50
            Megaseismul din 1755 de la Lisabona a fost probabil provocat de anumite fenomene (nelamurite inca pe deplin) produse in Oceanul Alantic. Un alt cutremur similar, aproape la fel de dezastruos, s-a produs langa Lisabona pe 26 ianuarie 1531. Putem presupune ca asfel de cutremure nu sunt simple evenimente seismice locale, ci sunt fenomene care se manifesta la nivelul Oceanului Atlantic, cutremurul din 1 noiembrie 1755 fiind urmat (pe 18 noiembrie 1755) de un cutremur pe celalalt tarm al oceanului, langa Cape Ann, in Massachusetts.

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            • #51
              24 noiembrie 1976: cutremur major cu magnitudinea Mw 7,3 in Estul Turciei, zona Caldiran, cu urmari catastrofale. Seismul devastator de la Çaldıran–Muradiye s-a produs dupa seismul vrancean moderat din 1 octombrie 1976 si a precedat cutremurul major din 1977. De altfel, in perioada 1971-1976 s-au produs mai multe cutremure mari in Turcia, Iran, Uzbekistan si China.

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              • #52
                26 decembrie 2004: megaseismul din Oceanul Indian: Nordul Sumatrei Simeulue-Nicobar-Andaman Mw 9,1 cu tsunami catastrofal (peste 200.000 de victime in Indonezia, dar si in Thailanda). Contextul in care s-a produs acest megaseism a fost urmatorul:

                25 martie 1998: megaseism in zona Balleny din Sudul Oceanului Indian Mw 8,1;
                4 iunie 2000: cutremur major in Sumatra-Engganno Mw 7,9;
                18 iunie 2000: cutremur major in zona Ins. Cocos, Oceanul Indian Mw 7,9

                Cele 3 cutremure mari au fost semne ale unei perturbatii majore la nivel global, generate de placa Indo-Australiana, cu rezultate care s-au vazut pana in 2004 si chiar si dupa 2004, urmand alte megaseisme cum au fost cele din 28 martie 2005 (Nias, Mw 8,7), 12 septembrie 2007 (Kep Mentawai Mw 8,5), 11 aprilie 2012 (Ninety Ridge Mw 8,6 si Mw 8,2), 2 martie 2016 (la sud de Ninety Ridge, Mw 7,8). Megaseismul din 26 decembrie 2004 a fost precedat de un alt megaseism produs pe 23 decembrie 2004 in zona Macquarie, la Sud de Australia (Mw 8,1).

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                • #53
                  26 decembrie 2003: cutremur distrugator in Sud-Estul Iranului, zona orasului Bam (Mw 6,6).

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                  • #54
                    9 ianuarie 1857: marele cutremur de la Fort Tejon, pe partea sudica a faliei San Andreas, zona Parkfield, de fapt (Mw 7,9).

                    https://www.usgs.gov/natural-hazards...center_objects

                    This earthquake occurred on the San Andreas fault, which ruptured from near Parkfield (in the Cholame Valley) almost to Wrightwood (a distance of about 300 kilometers); horizontal displacement of as much as 9 meters was observed on the Carrizo Plain. It caused one fatality. A comparison of this shock to the San Francisco earthquake, which occurred on the San Andreas fault on April 18, 1906, shows that the fault break in 1906 was longer but that the maximum and average displacements in 1857 were larger.

                    1857_01_09_loc.gif

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                    • #55
                      12 ianuarie 2010: cutremur devastator in Haiti, cu magnitudinea Mw 7,0. Seismul a avut urmari catastrofale din cauza faptului ca a fost de adancime mica si, in plus, starea constructiilor de acolo era sub orice critica, practic a ras mare parte din infrastructura, cladiri oficiale, locuinte, in special in apropierea epicentrului.

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                      • #56
                        17 ianuarie 1994: cutremur distrugator in California, zona Northridge, langa Los Angeles. Seismul, cu magnitudinea Mw 6,7, a distrus mai multe autostrazi suspendate si a provocat incendii.

                        17 ianuarie 1995: cutremur devastator la Kobe, Japonia, cu urmari catastrofale, distrugeri majore si mii de victime. Totusi, prin magnitudine (Mw 6,9-7,2), acest seism este departe a putea fi considerat foarte mare pentru ce poate fi in Japonia d.p.d.v. seismic.

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                        • #57
                          23 ianuarie 1556: cutremur catastrofal in China, provincia Shaanxi, magnitudine estimata Mw > 8,0, efecte distrugatoare, mari alunecari de teren, 830.000 de victime.

                          https://en.wikipedia.org/wiki/1556_Shaanxi_earthquake

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                          • #58
                            27 ianuarie 2003: cutremur puternic cu magnitudinea Mw 6,1 in zona Pulumur-Erzincan, Estul Turciei. Acesta a fost unul dintre cele doua cutremure produse in Estul Turciei in 2003, cu mecanisme de decrosare, si care au precedat cutremurul vrancean din 2004. A mai fost cutremurul din 1 mai 2003 de la Bingol, pe falia Est-Anatoliana, cu Mw 6,4.

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                            • #59
                              26 martie 1872: cutremur major in Owens Valley, California: Mw intre 7,4 si 7,9 (estimare).

                              Description:
                              The 1872 Lone Pine earthquake struck on March 26 at 02:30 local time with an estimated moment magnitude of 7.4 to 7.9 and a maximum Mercalli Intensity of X (Extreme). Its epicenter was near Lone Pine, California, in Owens Valley. It was one of the largest earthquakes to hit California in recorded history and was similar in size to the 1906 San Francisco earthquake. Twenty-seven people were killed and fifty-six were injured.



                              The earthquake occurred on a Tuesday morning and leveled almost all the buildings in Lone Pine and nearby settlements. Of the estimated 250–300 inhabitants of Lone Pine, 27 are known to have perished and 52 of the 59 houses were destroyed. One report states that the main buildings were thrown down in almost every town in Inyo County. About 130 kilometers (81 mi) south of Lone Pine, at Indian Wells, Kern County, California, adobe houses sustained cracks. Property loss has been estimated at $250,000 (equivalent to $5,228,472 in 2018). As in many earthquakes, adobe, stone and masonry structures fared worse than wooden ones which prompted the closing of nearby Camp Independence which was an adobe structure destroyed in the quake.

                              The quake was felt strongly as far away as Sacramento, where citizens were startled out of bed and into the streets. Giant rockslides in what is now Yosemite National Park woke naturalist John Muir, then living in Yosemite Valley, who reportedly ran out of his cabin shouting, "A noble earthquake!" and promptly made a moonlit survey of the fresh talus piles. This earthquake stopped clocks and awakened people in San Diego, California, to the south, Red Bluff, California, to the north, and Elko, Nevada, to the east. The shock was felt over most of California and much of Nevada. Thousands of aftershocks occurred, some severe.

                              https://en.wikipedia.org/wiki/1872_O...ley_earthquake

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                              • #60
                                11 aprilie 2012: megaseismele cu mecanisme de decrosare de pe Ninety Ridge-Nordul Sumatrei, Oceanul Indian (primul cu Mw 8,6 si al doilea cu Mw 8,2), sucedate la cateva ore. Desprinderea violenta a partii Indiene a avut efecte rapide la scara globala, efecte care s-au propagat pana in Vrancea (cutremurele moderate din 2013, 2014, 2016 si 2018).

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