1960年智利大地震:有记录以来最大的地震

The Setting: Chile's Subduction Zone

Chile occupies one of the most seismically active strips of land on Earth. The Nazca Plate subducts beneath the South American Plate along the Peru-Chile Trench at a rate of about 7 centimeters per year, making the 俯冲带一个构造板块潜入另一板块之下并进入地幔的区域。俯冲带产生世界上最大的地震（8.5级以上），并伴有深海沟和火山弧。 one of the most productive sources of large earthquakes on the planet. Historical records document dozens of major earthquakes along the Chilean coast, and the country had experienced multiple catastrophic events in the 20th century alone, including a M8.2 earthquake in 1939 that killed approximately 30,000 people. Chilean culture and architecture had some familiarity with seismic hazard, but the remote and rural areas of southern Chile — Los Lagos and Araucanía regions — had relatively simple timber and adobe construction.

The Earthquake: May 22, 1960

At 3:11 PM on May 22, 1960, the Nazca Plate lurched beneath the South American Plate along a rupture zone stretching approximately 1,000 kilometers from the city of Temuco in the north to Chiloé Island in the south. The earthquake lasted approximately 10 minutes — extraordinarily long even by megathrust standards — and released more seismic energy than any other event in the instrumental era. The 矩震级衡量地震规模的现代标准（Mw），基于地震矩——即断层面积、平均滑动量与岩石刚度的乘积。对任何规模的地震都能给出准确结果。 was determined to be M9.5, a value that has never been exceeded in recorded history. To put this in context: the 地震能量地震辐射出的总地震能量，以焦耳为单位测量。9级地震释放的能量约相当于25,000颗核弹。 released by the 1960 Chile earthquake was approximately 25 percent of all the seismic energy released by earthquakes worldwide between 1906 and 2005. The rupture area was so large that 地震波由地震或爆炸产生并在地球内部传播的弹性波。地震波将震源释放的能量传送到远处地点。 oscillations could be detected for weeks afterward as the Earth rang like a bell — the phenomenon known as free oscillations of the Earth, which was first measured clearly after this earthquake and became a major tool of deep Earth 地震层析成像利用地震波走时构建地球内部三维结构图像的技术，类似于医学CT扫描，可揭示地幔柱、俯冲板片等深部结构。.

The Science: The World's Largest Earthquake

The 1960 Chile earthquake was pivotal to the development of 矩震级衡量地震规模的现代标准（Mw），基于地震矩——即断层面积、平均滑动量与岩石刚度的乘积。对任何规模的地震都能给出准确结果。 as the standard measure of earthquake size. The 里氏震级查尔斯·里克特于1935年提出的最初对数震级标度，用于测量地方性地震的震级。如今已在很大程度上被矩震级取代，但媒体报道中仍常被提及。 and 面波震级（Ms）基于周期约20秒的瑞利波振幅确定的震级标度。适用于浅源地震，但在震级8.0以上会出现饱和现象。 scales saturate — they cannot accurately represent events above roughly M8.5 because the seismic waves used to compute them reach maximum amplitudes that don't scale linearly with actual energy release. The moment magnitude formula, developed by Kanamori and Hanks in the 1970s, uses the 地震矩衡量地震释放总能量的指标，由断层面积、平均位移量与岩石的剪切模量相乘计算得出，是矩震级的计算基础。 — the product of fault area, average slip, and rock rigidity — to compute a magnitude that does not saturate. Applied retroactively to the 1960 Chile earthquake using geodetic data, tide gauge records, and field observations of coastal deformation, the M9.5 value emerged from calculations of the enormous fault area (roughly 1,000 km by 150 km) multiplied by the estimated average slip of approximately 20 meters. The earthquake also generated a 海啸由水下地震导致海底突然位移而产生的一系列海浪。海啸可以喷气机般的速度（时速700公里以上）穿越整个大洋盆地。 that became one of the most studied in history. The initial waves struck the Chilean coast within minutes, killing an estimated 1,000 to 6,000 people — figures are uncertain because the coastal devastation was so complete. The 海啸由水下地震导致海底突然位移而产生的一系列海浪。海啸可以喷气机般的速度（时速700公里以上）穿越整个大洋盆地。 then propagated across the Pacific Ocean. Fifteen hours after the earthquake, waves 10 to 11 meters high struck Hilo, Hawaii, killing 61 people. Twenty-two hours after the earthquake, waves 6 meters high struck the coast of Japan, killing 142 people. The 1960 海啸由水下地震导致海底突然位移而产生的一系列海浪。海啸可以喷气机般的速度（时速700公里以上）穿越整个大洋盆地。 was the first to clearly demonstrate the global reach of Pacific megathrust tsunamis and directly motivated the expansion of the Pacific Tsunami Warning System.

The Impact: Continental-Scale Destruction

The immediate casualties from the earthquake and tsunami in Chile are difficult to establish precisely. Estimates range from 1,655 to over 6,000 deaths, with the wide range reflecting the difficulty of counting casualties in remote areas with destroyed infrastructure. Approximately 2 million people were left homeless. The coastal landscape was permanently altered: sections of coastline subsided by as much as 2 meters, while other areas were uplifted. Lakes formed where none had existed. The Valdivia River was temporarily blocked, creating flooding upstream. The 地震波由地震或爆炸产生并在地球内部传播的弹性波。地震波将震源释放的能量传送到远处地点。 energy triggered volcanic eruptions at the Cordón Caulle volcanic complex, beginning just 47 hours after the mainshock — an example of how mega-earthquakes can modify the stress field in ways that influence volcanic activity. The 海啸由水下地震导致海底突然位移而产生的一系列海浪。海啸可以喷气机般的速度（时速700公里以上）穿越整个大洋盆地。 caused damage as far away as Japan and the Philippines, demonstrating that this event's 地震能量地震辐射出的总地震能量，以焦耳为单位测量。9级地震释放的能量约相当于25,000颗核弹。 transcended its local geography and became a truly global disaster. Use the Earthquake Energy Calculator to compare the energy of this M9.5 event to the next-largest recorded earthquakes — the difference is staggering.

The Response and Legacy

Chile's response to the 1960 earthquake was shaped by the simultaneous political and economic crises facing the country under President Jorge Alessandri. International aid from the United States, Soviet Union, and European nations helped fund reconstruction. The earthquake directly motivated the modernization of Chile's 抗震建筑规范为确保建筑物达到最低地震安全水平而制定的一套法律要求，涉及建筑的设计与施工，通常在重大地震暴露出新的薄弱环节后进行修订。, which became one of the more rigorous in Latin America over subsequent decades — a factor that would prove crucial when Chile faced another M8.8 earthquake in 2010. The 1960 event's global 海啸由水下地震导致海底突然位移而产生的一系列海浪。海啸可以喷气机般的速度（时速700公里以上）穿越整个大洋盆地。 impact forced the Pacific Tsunami Warning System to expand its scope and improve its modeling capabilities. In Japan, the disaster motivated the construction of seawalls along the Sanriku coast — the same seawalls that were later overtopped by the 2011 Tohoku tsunami. The 1960 Chile earthquake also entered the scientific consciousness as proof that the Earth's tectonic system is capable of releasing energy at a scale that defies intuition: 1,000 kilometers of fault rupture, 20 meters of average slip, and a tsunami that crossed the world's largest ocean as a coherent, deadly wave. This single event reshaped seismology, ocean science, and emergency management simultaneously.