Seismicity of Mars

Earth-bound seismology:

Seismology here on the Earth is all about earthquakes. It is basically the study of how the ground shakes as a result of a fault breaking following a buildup of pressure. People study them for two reasons. The first is that earthquakes do a lot of damage and people want to be able to predict when a large event may occur and to be able to mitigate the damage when one does, by building houses that can withstand the shaking. The second is to look at the waves that go deep into the Earth (see figure 1). These act a little like sonar pulses, reflecting off boundaries between different rock types and off the boundaries between the crust, mantle and core. Seismic waves have allowed us to map the interior of our planet in startling detail and to understand the processes that occur deep beneath our feet. We now want to take this tool out into the solar system to map the other planets.

Seismic waves in the Earth

Figure 1 – Seismic waves in the Earth

Martian Seismology:

In 2016 the InSight geophysical mission to Mars is due to ‘set sail’ (see my previous post). It will carry two seismometers, one capable of detecting large earthquakes from anywhere across the planet, and one that will measure much higher-frequency waves from small, local quakes. The first is a ‘broadband’ instrument which seismologists use to look at the deep structure of the planet, using the waves that penetrate deeply enough to bounce off the core! The second is known as a ‘short-period’ instrument which is able to map the small details of the structure in the crust. Combined, these instruments will give us an excellent picture of the interior of Mars; the first detailed look at the inside of a planet other than our own.

However, before we get there in 2016, there is a lot of work to be done. We first need to get an idea of whether our instruments are going to measure any Marsquakes at all. Will there be any such events? Will they be large enough for us to detect? How will the lander be placed relative to likely seismic sources? All of these questions need answering so that our instruments aboard InSight can be fine-tuned. This is where I come in.

My research aims to estimate how much active seismicity we expect to observe on the Red Planet by looking at faults close to the landing site. These faults, known as the Cerberus Fossae (see figure 2) are around 1000km from the proposed landing site. This figure is taken from a paper by Roberts et al. which shows evidence that these faults are likely still active today.

Figure 2 - Cerberus Fossae

Figure 2 – Cerberus Fossae

My newest results also show that Mars may be far more seismically active than has previously been thought. Stay tuned to find out more!

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