Earthquakes can pose some issues for commercial passenger aircraft, but not due to the waves generated by the ground shaking.
It may sound unbelievable, but depending on the situation, earthquakes can lead to certain consequences that may cause flights to encounter problems. First, let’s explore the relationship between the atmosphere and the ground.
“The ground shaking can generate extremely small atmospheric waves that can travel directly to the ionosphere,” said Attila Komjathy, a scientist at NASA’s Jet Propulsion Laboratory (JPL). The ionosphere is a layer of the atmosphere dense with molecules and charged particles, starting at about 60 kilometers and extending to heights of approximately 1,000 kilometers above the Earth’s surface.
Passengers on commercial flights need not worry when flying over earthquake zones. (Photo: IFL Science).
Thus, earthquakes can cause some disturbances in the atmosphere, but is this enough to cause commercial passenger aircraft to experience incidents? The answer is no.
Earthquakes release seismic waves in the form of pressure waves (P-waves) and shear waves (S-waves). S-waves can only travel through solid mediums (the ground), but P-waves can travel through other mediums such as liquids or gases. This means that they can propagate into the atmosphere. When this occurs, they become sound waves with frequencies usually below 20 hertz—the lowest threshold detectable by humans—so people typically cannot hear them. Sounds with frequencies below 20 hertz are referred to as infrasound.
The farther sound waves travel through the air, the weaker they become. This process is known as attenuation. Essentially, this is the process that makes everything quieter as the listener moves farther from the sound source, or causes sunlight to diminish as it passes through different layers of the atmosphere or other mediums, such as the ocean.
This is why aircraft flying over areas experiencing earthquakes, even strong ones, will not feel the effects of the tremors below. As they propagate through rock and then into the air, P-waves weaken to the point that they are overshadowed by the aircraft’s own movement and noise.
However, this does not mean that aircraft are completely risk-free during an earthquake. The issues here belong to a different category, related to safety and navigation.
In response to a question on the Quora Q&A forum in 2018, U.S. Air Force pilot and aerospace engineer Ron Wagner stated that he had flown during an earthquake that affected air traffic control. Specifically, the earthquake caused a power outage at the ground base, leading to issues with navigation equipment as well as the aircraft’s communication capabilities. The power outage also meant that the air traffic control unit lost radar signals and could not locate Wagner’s aircraft. Nonetheless, all these issues were temporary and resolved once the ground base’s emergency power kicked in.
Typically, air traffic control stations are equipped with enough backup generators for situations like this. They are also well-prepared with contingency plans for disasters such as volcanic eruptions, nuclear fallout dust, floods, terrorism, and even earthquakes. Therefore, passengers need not worry if they are flying while an earthquake occurs below. In most cases, passengers may not even be aware that an earthquake has taken place until they land.
