A new era of earthquake science
The Tashkent seismic station is a foundational site in modern seismology. Established as part of a network of stations across the Russian Empire, it was equipped with some of the most advanced instruments of its time. Prince Boris Golitsyn, a Russian physicist, invented the first electromagnetic seismograph in 1906. These devices represented a major technological advance. Instead of purely mechanical systems, Golitsyn's seismographs used an induction coil moving within a magnetic field to generate an electrical current proportional to the ground's velocity. This current was then recorded by a galvanometer, allowing for much more sensitive and accurate measurements of seismic waves from distant earthquakes. The installation of these instruments positioned Tashkent at the forefront of geophysical observation in the early 20th century.
The station's continuous operation through decades of political and social change provided an invaluable, long-term record of regional seismicity. This data became globally significant in the spring of 1966. The station's instruments observed distant tremors; they were about to record a catastrophic event happening directly beneath them. This event would provide a dataset that altered the scientific understanding of seismic hazards in urban areas.
The ground truth of 1966
On April 26, 1966, at 5:23 AM local time, a magnitude 5.2 earthquake struck Tashkent. While moderate in magnitude, its effects were devastating. The reason was its extremely shallow hypocenter, located just 3 to 8 kilometers directly beneath the city center. This proximity to the surface generated intense vertical ground shaking, a phenomenon less understood at the time compared to the more commonly studied horizontal shear waves. The traditional adobe and brick buildings, which formed much of the historic city, were not built to withstand such forces.
The earthquake destroyed over 80% of the city, leaving more than 300,000 people homeless. The near-field recordings from the Tashkent station were unprecedented. They gave seismologists and engineers a direct look at how seismic waves propagate through and amplify within a metropolitan area. The data revealed the nature of ground motion and the specific vulnerabilities of urban construction to shallow-focus quakes. In the aftermath, Soviet authorities established the Institute of Seismology in Tashkent on October 1, 1966, to forecast future earthquakes and develop safer building codes. The station's 1966 recording, along with data from over 1,100 aftershocks logged by 1969, became a case study for urban seismic risk assessment worldwide.