The tomb of Cyrus the Great, dating back over 2,500 years, is considered the oldest structure with effective earthquake-resistant design.
In ancient Greece and Persia, a construction technique was developed where materials such as ceramics and clay were inserted between the ground and the foundation. This allowed layers to slide over one another during seismic activity, minimizing damage caused by earthquakes, according to Amusing Planet. This technique is known as base isolation, and it remains one of the most effective measures for protecting buildings from earthquakes today. The earliest example of base isolation is the tomb of Cyrus located in Pasargadae, the capital of the Achaemenid Empire during the reign of Cyrus the Great (559 – 530 BC) in Iran.
Tomb of Cyrus the Great. (Photo: Borna_Mirahmadian).
Despite Cyrus the Great ruling over a vast kingdom that extended from the Mediterranean Sea to the Indus River, his tomb is remarkably simple and modest. The tomb has a cubic shape with dimensions of 6 x 5 meters. A small door leads down to the burial chamber. The roof of the tomb is triangular. The tomb chamber is situated above a pyramidal base consisting of six large steps. It is constructed from massive stone blocks.
The foundation of the tomb is made of several layers of limestone. The first layer is built with stones bonded with mortar, which includes a mixture of lime mortar and ash or sand, and is then smoothed. The upper layer consists of stones connected by metal rods but is not attached to the layer below. This design allows the upper layer to slide over the lower layer in the event of an earthquake.
The tomb of Cyrus has withstood numerous earthquakes over the past 2,500 years, although researchers are unsure of their magnitudes or whether they were strong enough to activate the “base isolation” structure. They have not found any signs of displacement in the stones and layers. To date, they have not been able to definitively determine whether the pyramidal structure was indeed designed with “base isolation” principles to protect the tomb.
According to the Greek historian Arrian of Nicomedia, who served as a general under Alexander the Great, the Macedonian king visited the tomb after plundering Persepolis. Alexander commanded one of his soldiers, Aristobulus, to enter the tomb. Inside, he discovered a golden bed, a table with a drinking vessel, a golden sarcophagus, and several decorative items adorned with jewels.
A detailed study by Islamic Azad University in Iran suggests that the base isolation system at the tomb of Cyrus the Great actually exists. They simulated the tomb using software and subjected it to strong earthquake conditions before drawing their conclusions.
