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![]() Claudio Scarpati
After the eruption of Mount Vesuvius, many Pompeiians fled into the streets in an attempt to escape the rain of pumice, gas and rock. The figure in this cast was among the hundreds of victims who never made it to safety.
据国外媒体报道,公元79年,维苏威火山突然灾难性爆发长达19个多小时,庞培古城因此而遭大量火山灰湮没,数千人死亡。在厚6米的火山灰覆盖下,这座城市得以保存,为今人提供了有关古人生活状态的珍贵信息,意大利那不勒斯—腓特烈二世纳布里大学的火山学家克劳德·斯卡帕迪及其同事得以重现庞培家族的最后时刻。
科学家分析了庞培房子里的火山灰,检查了火山灰下掩埋的13具尸骨,再现了维苏威火山爆发时所出现的情景。该研究小组将他们的发现近日发表在那不勒斯举行的有关古老DNA的国际会议上。阿波坦查大道(Via dell Abbondanza)是庞培的主要街道,这里的波利比奥斯(Polybius)房子是最值得研究的地方之一。斯卡帕迪表示这处房子出产了丰富多样的考古发现。而且,这里最能体现庞培火山灰完整的堆积层。
在公元79年8月24日下午大约1点钟,庞培居民们看到松树形的烟尘云从维苏威火山喷发出来,冲到了14公里的高空。接着,烟尘云开始下起浓密的浮石雨。许多居民冲向街道,努力逃离这所城市。斯卡帕迪表示,此时,波利比奥斯房子住着12个人,包括一位怀孕了的年轻女人。他们决定留在房子里,因为大多数认为这样对孕妇更为安全些。“在这种状况下,这是明智的选择。”
据火山学家分析,第一阶段的火山爆发实际上只导致了38人死亡。斯卡帕迪表示,而先前认为大多数死亡出现在维苏威火山爆发的头一个小时。许多逃亡的尸骨表明有断裂的骨骼,意味着他们死于房顶坍塌或从喷发出来的火山烟尘云中掉落下来的大块碎石。
通过检查火山灰的密度,科学家发现其堆积速度为每小时6英寸(相当于15厘米)厚,因此导致波利比奥斯(Polybius)房子的房顶坍塌得需要6个小时。大约下午7点,波利比奥斯家人在后面的房间里找到了躲藏处,因为这里更加陡峭的屋顶没有被掉下来的东西砸坏。斯卡帕迪表示,这里有三名成年男子,三名不同年龄段的成年女人和4个男孩、一个女孩和一个已经足月的胎儿。而且,此胎儿和这位16—18岁的年轻女人的尸骨在一起。
通过分析线粒体DNA,揭示其中6人属于同一家庭,其中5人的年龄表明他们是兄弟姐妹。另一位大约25—30岁的人可能是堂兄弟。三位成年女人没有血缘关系。DNA分析还表明其中二位亲戚患有脊柱裂。脊柱裂为脊椎轴线上的先天畸形。最常见的形式为棘突及椎板缺如,椎管向背侧开放,以骶尾部多见,颈段次之,其他部位较少。病变可涉及一个或多个椎骨,有的同时发生脊柱弯曲和足部畸形。脊柱裂常与脊髓和脊神经发育异常或其他畸形伴发,少数伴发颅裂。
研究人员表示,波利比奥斯房子里的人最可能包括父母和他们的孩子、一位堂兄弟和他年轻的怀孕妻子,外加二位佣人。他们目击此火山可怕的爆发情景,在8月25日的早晨,近3米深的火山灰已经完全覆盖了街道和建筑物的地基。波利比奥斯一家全部死在其房子后面的房间里。
斯卡帕迪表示,一些火山灰下的尸骨姿势表明他们死时正在床上睡觉。当第一阶段的火山爆发结束后,火山爆发的烟尘云坍塌,产生了一系列的火山碎屑流。这是快速流动的气体和熔岩流,其温度达到了200到700摄氏度。“首批火山碎屑流从北流来,覆盖了此房子的后面部分。之后再流经花园,到达房子的前部分。没有人能从这里逃脱出来。火山灰遍及房子的各个角落,让屋里的人窒息而死。”然而,火山灰层揭示并非所有的庞培居民都是因毁灭性的气体和岩石流致死。“我们发现有死者位于此气体和岩石流所形成的基底火山灰层上面几厘米的地方。一些居民行走在屋外得以幸存到第二波火山碎屑流的到来。”
在上午7—8点,最后一波火山爆发产生更多的浮石雨,埋葬了庞培。波利比奥斯房子的牢固的房顶坍塌了,剩下死亡一般的长久沉静。斯卡帕迪表示,这种火山爆发很难让人幸存下来。“虽然我们估计有75—92%的庞培人在第一波火山爆发时逃离了庞培,但不知道他们是否逃脱成功了。有好几百受害者埋葬在城墙外的小挖掘坑里
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Italian researchers have reconstructed the last hours in Pompeii of a dozen people who managed to survive Mount Vesuvius' devastating eruption for more than 19 hours.
Volcanologist Claudio Scarpati, and colleagues Giuseppe Luongo and Annamaria Perrotta of the University of Naples Federico II in Italy, analyzed layers of volcanic deposits in a Pompeian house and examined 13 skeletons found there on a carpet of pumice to reconstruct the events that occurred when the eruption was in progress. The team reported their findings at a recent international conference on ancient DNA in Naples.
Located in Pompeii's main street, Via dell'Abbondanza, the home of Iulius Polybius is one of the most studied in the ancient Roman town.
"This house has yielded rich and diverse archaeological findings. Moreover, it features the most complete stratified sections of Pompeii's volcanic deposit," Scarpati told Discovery News.
At around 1:00 p.m. on Aug. 24, 79 A.D., Pompeii residents saw a pine tree-shaped column of smoke bursting from Vesuvius. Reaching nine miles into the sky, the column began spewing a thick pumice rain. Many residents rushed in the streets, trying to leave the city.
"At that moment, Polybius' house was inhabited by 12 people, including a young woman in advanced pregnancy. They decided to remain in the house, most likely because it was safer for the pregnant woman. Given the circumstances, it was the right strategy," Scarpati said.
Once considered relatively innocuous by volcanologists, this first phase of the eruption in fact produced 38 percent of the deaths.
"Contrary to what was previously believed, a large number of deaths occurred in the first hours of the eruption. Many skeletons of those who tried to escape show fractured skulls, meaning that they died from collapsing roofs or large fragments falling from the eruptive column," Scarpati said.
By examining the density of volcanic deposits in relation to an accumulation rate of six inches per hour, the researchers concluded that it took up to six hours for the roofs of Polybius' house to collapse.
At around 7:00 p.m., by which time the front part the house had collapsed, the inhabitants took shelter in the rear rooms, whose steeper roofs had not been damaged by the falling material.
"There were three adult males, three adult females of various ages, four boys, one girl, one child and one fetus in the last month of intrauterine life. The fetus was associated with the skeleton of a young (16 to 18-year-old) female," Scarpati said.
Analysis of mitochondrial DNA, which is passed down through the maternal line, revealed that six individuals belonged to the same family.
"The age of five out of six individuals suggests that they were siblings. Another subject, about 25 to 30 years old, might have been a cousin. The three adult women were unrelated," molecular biologist Marilena Cipollaro, of the Second University of Naples, told Discovery News.
Cipollaro's analysis also revealed that two related subjects suffered from spina bifida, a birth defect resulting in an incomplete closure of the spinal column.
Most likely, the group of people in Polybius' house included the parents, their children, a cousin and his young, pregnant wife, plus a pair of servants.
They all witnessed the terrible evolution of the eruption. In the early hours of Aug. 25, a nearly 10-foot-thick carpet of pumice had already covered the streets and bottoms of buildings.
Polybius' family perished in their home's back rooms.
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When the first phase of the eruption ended, the eruptive column collapsed, producing a series of pyroclastic currents. These are fast-moving flows of hot gas and rock at temperatures ranging from 392 to 1,292 degrees Fahrenheit.
"The first pyroclastic currents arrived from the north and overtopped the rear part of the house. The currents moved into the garden and advanced toward the front of the house. No escape was possible for the people there. The ash reached every corner in the house and suffocated its inhabitants," Scarpati said.
Ash layers revealed that not all Pompeii residents were killed by the devastating wave of gas and rock.
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"We found victims several centimeters above the basal ash layers related to this current. Some residents walked outdoors and survived until the second pyroclastic current," Scarpati said.
Between 7:00 and 8:00 a.m., a final phase, punctuated by more pumice rain, buried Pompeii.
The solid roofs of Polybius' house collapsed. What followed was a long, deathly silence.
"It was impossible to survive that eruption. Even though we calculated that 75 to 92 percent of the residents escaped the town at the first signs of the crisis, it is not possible to know how successful those fugitives were. Hundreds of victims were recovered from the relatively small excavations outside the city walls," Scarpati said.
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