Venezuela’s Powerful Earthquakes Were a Rare ‘Seismic Doublet’
Venezuela’s Powerful Earthquakes Were a Rare ‘Seismic Doublet’
委内瑞拉强震：罕见的“地震双震”现象
Venezuela declared a national emergency following two earthquakes of 7.2 and 7.5 magnitude that occurred just 39 seconds apart on Wednesday. This phenomenon, known as a seismic doublet, is rare. 周三，委内瑞拉发生两起地震，震级分别为 7.2 级和 7.5 级，两次地震间隔仅 39 秒，该国随后宣布进入国家紧急状态。这种被称为“地震双震”（seismic doublet）的现象十分罕见。
However, there are documented cases in various regions of the world that continue to be studied to expand our understanding of the mechanisms of stress is transferred within the Earth’s crust and the interaction between geological faults. 然而，世界各地已有相关案例记录，科学家们持续对其进行研究，以加深我们对地壳内应力传递机制以及地质断层间相互作用的理解。
The US Geological Survey reported that both earthquakes had their epicenters northwest of the town of Yumare, near the city of Morón and about 160 kilometers (99 miles) west of the Venezuelan capital of Caracas. The quakes occurred at depths of 20.3 and 10 kilometers and were felt across much of northern Venezuela and in several Caribbean countries. 美国地质调查局（USGS）报告称，两次地震的震中均位于尤马雷（Yumare）镇西北部，靠近莫龙（Morón）市，距离委内瑞拉首都加拉加斯以西约 160 公里（99 英里）。地震震源深度分别为 20.3 公里和 10 公里，委内瑞拉北部大部分地区及多个加勒比国家均有震感。
The sequence was classified as a severe seismic doublet, a phenomenon that occurs when two earthquakes of similar magnitude strike almost simultaneously in nearby areas. According to USGS estimates, the probability that an earthquake will be followed by another of greater magnitude in a nearby area within a week is approximately 5 percent. 此次地震序列被归类为严重的“地震双震”，即两场震级相近的地震在邻近区域几乎同时发生。据 USGS 估计，一场地震后一周内在附近区域发生更大震级地震的概率约为 5%。
One of the most significant seismic doublets in recent history occurred about three years ago in Turkey and Syria, when a 7.6-magnitude earthquake was followed by a 7.8-magnitude one. A study suggested that the phenomenon was the result of tectonic stress that had built up over more than two centuries along the fault responsible for the first quake. When it ruptured, it released stress that was transferred to a nearby fault, rapidly triggering the second event. 近代史上最显著的地震双震之一发生在约三年前的土耳其和叙利亚，当时一场 7.6 级地震后紧接着发生了 7.8 级地震。研究表明，该现象是导致第一次地震的断层上积累了两个多世纪的构造应力所致。当断层破裂时，释放的应力传递到了邻近断层，迅速引发了第二次地震。
How Does a Seismic Doublet Occur?
地震双震是如何发生的？
Experts believe a similar process may have occurred in Venezuela. Mark Allen, a professor in the Department of Earth Sciences at Durham University, explains in a statement reported by SMC Spain that “it is likely that the first earthquake caused a segment of the fault to rupture and transferred the stress to another fault, which in turn ruptured, triggering the second earthquake.” 专家认为，委内瑞拉可能也经历了类似的过程。杜伦大学地球科学系教授马克·艾伦（Mark Allen）在接受西班牙科学媒体中心（SMC Spain）采访时解释道：“很可能是第一次地震导致断层的一部分破裂，并将应力传递给了另一个断层，进而引发了第二次地震。”
Allen also noted that the geological characteristics of the region where the epicenters were located played an important role. “The events appear to have taken place at the plate boundary between South America and the Caribbean. In this region, the plates move laterally relative to one another, similar to what occurs along the San Andreas Fault in California,” he says. 艾伦还指出，震中所在区域的地质特征起到了重要作用。他说：“这些事件似乎发生在南美板块和加勒比板块的边界。在该区域，板块之间进行侧向移动，类似于加利福尼亚州的圣安德烈亚斯断层。”
These conditions favor the generation of strike-slip earthquakes, which occur when two blocks of the Earth’s crust move horizontally along a fault and suddenly release the stress accumulated over long periods. 这些条件有利于产生走滑型地震，即地壳的两块岩体沿断层水平移动，并突然释放长期积累的应力。
This type of movement often causes significant damage because it originates at relatively shallow depths. Unlike subduction earthquakes, which occur when one tectonic plate slides beneath another, strike-slip earthquakes tend to occur closer to the Earth’s surface. 这种类型的运动通常会造成严重破坏，因为它发生在相对较浅的深度。与一个构造板块滑入另一个板块下方引发的俯冲型地震不同，走滑型地震往往更靠近地表。
As a result, the energy released travels a shorter distance before reaching populated areas, which increases the intensity of the tremors felt and raises the risk of damage. 因此，释放的能量在到达人口稠密地区前传播距离较短，这增加了震感强度，并提高了受损风险。
Allen warned that, due to these circumstances, “there is a risk of further earthquakes (aftershocks) in the Caracas region. The Venezuelan capital is located in an area prone to seismic activity, and it is possible that local faults have been subjected to additional stress following the recent events.” 艾伦警告称，由于这些情况，“加拉加斯地区存在发生后续地震（余震）的风险。委内瑞拉首都位于地震多发区，近期事件可能导致当地断层承受了额外的应力。”
This forecast aligns with estimates from the USGS. The agency notes that, following earthquakes of this magnitude, seismic activity can continue for days, weeks or even longer. While frequency decreases over time, there’s still the possibility of powerful aftershocks. 这一预测与 USGS 的评估一致。该机构指出，在发生此类震级的地震后，地震活动可能会持续数天、数周甚至更长时间。虽然频率会随时间降低，但仍有可能发生强余震。
Official reports indicate that, so far, the two earthquakes recorded in Venezuela have claimed the lives of at least 164 people and left nearly 1,000 injured. The USGS estimates that the final death toll could range as high as 10,000 to 100,000 due to various factors related to the intensity of the quakes and the vulnerability, including construction quality and population density in the affected areas. 官方报告显示，截至目前，委内瑞拉记录的两起地震已造成至少 164 人死亡，近 1,000 人受伤。USGS 估计，由于地震强度以及受灾地区的建筑质量和人口密度等脆弱性因素，最终死亡人数可能高达 10,000 至 100,000 人。
This story originally appeared on WIRED en Español and has been translated from Spanish. 本文最初发表于《连线》西班牙语版，由西班牙语翻译而来。