Earthquake Prediction: Parkfield, San Andreas, and the Crystal Ball Search
Predicting earthquakes before they happen is currently impossible, but scientists are edging closer and closer with new and innovative ways to monitor movements in Earth’s crust. In this excerpt from “When Worlds Quake: The Quest to Understand the Interior of earth and Beyond” (Princeton University press, 2026), author Hrvoje Tkalčić,the head of geophysics at the Australian National University,delves into the reasons why earthquake prediction is so tricky,looking at the “Parkfield Experiment,” where scientists waited nearly 20 years for an earthquake on the San Andreas Fault to strike.
An approximate answer to these comments could be given with the following targeted question: “We still can’t beat malignant diseases, but should we stop researching as of that?”
We are used to discussions about earthquake causes after every event, particularly in the places where the world’s In 1979, a team of scientists began a 10-year experiment in Parkfield, California, a small town situated along the San Andreas Fault. Parkfield was known for its relatively regular earthquakes, occurring roughly every 22 years.The scientists aimed to predict the next earthquake in the area, hoping to unlock the secrets of earthquake prediction. They employed a variety of tools, including strainmeters to measure changes in the Earth’s crust, tiltmeters to detect subtle ground deformation, and even measured changes in the local magnetic field, creepmeters, which measure displacements on the surface along the fault, and other scientific “weaponry.” They forecasted with 90 to 95% confidence that the next earthquake ther would occur between 1985 and 1993. Some of the key questions were:
1. How is stress distributed in space and time on the fault due to the action of tectonic forces before and after the earthquake?
2. Do earthquakes repeat at an average time interval, or is each earthquake unique, a story in itself?
3. How do the structure of faults and surrounding rocks affect the nucleation of smaller earthquakes and the possibility of larger ones and their distribution in time and space?
This is possible because of basic science and seismological research on the nature of the subsurface, in a similar way that radiologists can illuminate the inside of the human body. Ironically, earthquakes help us as they serve as a source of waves illuminating the earth’s interior. It is possible to predict infrastructure behavior during earthquakes due to the advancement of engineering, construction, computer science and numerical methods. Either way, those hazar