１９７６年７月２８日，中国北京时间３时４２分，东经１１８．２度、北纬３９．６度，在距地面１６公里深处的地球外壳，比日本广岛爆炸的原子弹强烈４００倍的大地震发生了。中国新华通讯社于７月２８日向全世界发布了这一消息。几天以后再次公布了经过核定的地震震级：Ｍｓｔ７．８级。唐山，一座上百万人口的工业城市，在这场没有预报的特大地震中成为废墟。死亡人数达２４万之多。 就在这短短的几秒钟里，唐山市区和农村有６５万多间房屋倒塌和受到严重破坏。绝大多数唐山人均在睡眠状况下遭此浩劫。在许多奇迹般的生还者中有一位妇女，她从所住的旅馆逃出仅2秒钟，旅馆便断裂成两半，并坍塌了。由于惧怕还会发生更大的地震，大多数唐山人都转移到搭建在城外公路上供他们临时栖身的帐篷里。地震确切的死亡人数可能永远是个谜。官方公布的死亡人数是14.2万，但一些西方专家认为数字可能要高得多。
参考资料：求知网
我看到过很多数据, 底下所谓的官方数据是最少的. 1556年的华山大地震, 震级几乎相同, 死了80多万人, 1976年的唐山及周边人口的密度比五百年前关中要密很多, 仅仅死亡20多万, 不能不令人生疑.
下文说是死亡65万人.
The Great China Earthquake of 1556
The worse natural disaster in recorded history, at least in terms of lives lost, was caused by an earthquake in Hausien in the Shensi Province of China in 1556. The earthquake devastated 98 counties and eight provinces of Central China. The destruction spanned an area of 500 miles, and in some counties the average death toll was 60 percent of the population. A total of 830,000 people lost their lives, most of them from the collapse of poorly constructed houses. The magnitude of this earthquake has been estimated to be from 8.0 to 8.3 on the Richter scale.
The Haicheng Earthquake of February 4, 1975
On February 4, 1975, Haicheng, a town with about 100,000 inhabitants in the Liaoning Province of northeast China, was struck by a 7.3 magnitude earthquake. As early as 1970, the State Seismological Bureau, had identified the Liaoning Province as an area of high earthquake risk. Based on studies of precursor events and unusual animal behavior, a warning was issued by local authorities. Thus, when the earthquake struck on February 4, there were few lives lost as most inhabitants had evacuated to safer places. However property damage was high.
The China Earthquake of 1976
No other earthquake in this century has been as catastrophic or has claimed as many lives as the great earthquake that struck the city of Tangshan, in Northern China, on July 28, 1976.
Tangshan, a thriving industrial city with one million inhabitants, is located only about 95 miles east, and slightly south, of Beijing. Although the region had experienced moderate seismic activity in the past, the city of Tangshan has been built on unstable, alluvial soil. To make matters worse, The city is located in the center of an area with major crustal faults on four sides. Furthermore, a 25-mile long fault passes through Tangshan, where only few of its structures are earthquake-resistant.
In the early morning hours of July 28, while the city was asleep, the magnitude 8.0 earthquake with its epicenter right on the city broke a five-mile section of the fault. Along the west side of the fault the land moved five feet northward in relation to the land on the east side. The east block tipped downward at the northern end of the break, and upward toward the south end. Over a four-by-five mile area the devastation of the city was nearly total. The force of the quake motions were so strong that people reported being thrown in the air. Within seconds, thousands died. Property destruction was unbelievable. Bridges, railroads, homes, factories were completely leveled.
In the harbor city of Tientsin, 60 miles to the southwest, and in Beijing to the west, the quake jolts forced thousands of frightened people into the streets seeking refuge from aftershocks.
The extent of the destruction and number of deaths in Tangshan and elsewhere in China was never disclosed officially. However, based on the density of population, it was fairly accurately estimated that there were at least 655,000 people dead, and 780,000 injured. These figures make the 1976 Tangshan earthquake, the second worse earthquake in recorded history. The most destructive earthquake ever, as reported earlier, occurred at Hausien in China's Shensi Province in 1556.
