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replaced "bodies" with "planetoids" everywhere for the sake of consistency
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Jean-Marie Prival
Jean-Marie Prival
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A study by Stern et al. (2018) introduced a "Tectonic Activity Index" (TAI) to represent the tectonic activity of planetoids. The TAI is determined by looking at three criteria:

  • Recent deformation (faults and folds)
  • Recent volcanism
  • Recent resurfacing (impact craters abundance)

The presence of each criterion scores one point, so the TAI of a given planetoid can range between 0 and 3. The authors consider bodiesplanetoids with a TAI of 2 or 3 to be "tectonically alive", and planetoids with a TAI of 0 or 1 to be "tectonically dead". They determined the TAI of 26 planetoids of the Solar System. Mercury has a TAI of 1, while the Moon has a TAI of 0 (Table 1). Based on this, you could indeed say that Mercury is tectonically more active than the Moon.

However, by reading the paper, it is not all that clear how they came to this result, i.e., how Mercury got one point. Mercury and the Moon are often cited together as classic example of tectonically dead bodiesplanetoids. In the volcanism section, both are mentioned to have had volcanism in the early history of the Solar System. In the resurfacing section, both are mentioned to present a densely cratered surface. So I have the impression that Mercury scored one point for its deformation which, as the authors acknowledge, is due thermal contraction rather than internal convection.

In summary, both Mercury and the Moon are considered tectonically dead in terms of mantle convection, but the thermal contraction of Mercury triggers some kind of tectonic activity (reverse faulting) that is absent on the Moon.

A study by Stern et al. (2018) introduced a "Tectonic Activity Index" (TAI) to represent the tectonic activity of planetoids. The TAI is determined by looking at three criteria:

  • Recent deformation (faults and folds)
  • Recent volcanism
  • Recent resurfacing (impact craters abundance)

The presence of each criterion scores one point, so the TAI of a given planetoid can range between 0 and 3. The authors consider bodies with a TAI of 2 or 3 to be "tectonically alive", and planetoids with a TAI of 0 or 1 to be "tectonically dead". They determined the TAI of 26 planetoids of the Solar System. Mercury has a TAI of 1, while the Moon has a TAI of 0 (Table 1). Based on this, you could indeed say that Mercury is tectonically more active than the Moon.

However, by reading the paper, it is not all that clear how they came to this result, i.e., how Mercury got one point. Mercury and the Moon are often cited together as classic example of tectonically dead bodies. In the volcanism section, both are mentioned to have had volcanism in the early history of the Solar System. In the resurfacing section, both are mentioned to present a densely cratered surface. So I have the impression that Mercury scored one point for its deformation which, as the authors acknowledge, is due thermal contraction rather than internal convection.

In summary, both Mercury and the Moon are considered tectonically dead in terms of mantle convection, but the thermal contraction of Mercury triggers some kind of tectonic activity (reverse faulting) that is absent on the Moon.

A study by Stern et al. (2018) introduced a "Tectonic Activity Index" (TAI) to represent the tectonic activity of planetoids. The TAI is determined by looking at three criteria:

  • Recent deformation (faults and folds)
  • Recent volcanism
  • Recent resurfacing (impact craters abundance)

The presence of each criterion scores one point, so the TAI of a given planetoid can range between 0 and 3. The authors consider planetoids with a TAI of 2 or 3 to be "tectonically alive", and planetoids with a TAI of 0 or 1 to be "tectonically dead". They determined the TAI of 26 planetoids of the Solar System. Mercury has a TAI of 1, while the Moon has a TAI of 0 (Table 1). Based on this, you could indeed say that Mercury is tectonically more active than the Moon.

However, by reading the paper, it is not all that clear how they came to this result, i.e., how Mercury got one point. Mercury and the Moon are often cited together as classic example of tectonically dead planetoids. In the volcanism section, both are mentioned to have had volcanism in the early history of the Solar System. In the resurfacing section, both are mentioned to present a densely cratered surface. So I have the impression that Mercury scored one point for its deformation which, as the authors acknowledge, is due thermal contraction rather than internal convection.

In summary, both Mercury and the Moon are considered tectonically dead in terms of mantle convection, but the thermal contraction of Mercury triggers some kind of tectonic activity (reverse faulting) that is absent on the Moon.

Source Link
Jean-Marie Prival
Jean-Marie Prival
  • 201
  • 2
  • 7

A study by Stern et al. (2018) introduced a "Tectonic Activity Index" (TAI) to represent the tectonic activity of planetoids. The TAI is determined by looking at three criteria:

  • Recent deformation (faults and folds)
  • Recent volcanism
  • Recent resurfacing (impact craters abundance)

The presence of each criterion scores one point, so the TAI of a given planetoid can range between 0 and 3. The authors consider bodies with a TAI of 2 or 3 to be "tectonically alive", and planetoids with a TAI of 0 or 1 to be "tectonically dead". They determined the TAI of 26 planetoids of the Solar System. Mercury has a TAI of 1, while the Moon has a TAI of 0 (Table 1). Based on this, you could indeed say that Mercury is tectonically more active than the Moon.

However, by reading the paper, it is not all that clear how they came to this result, i.e., how Mercury got one point. Mercury and the Moon are often cited together as classic example of tectonically dead bodies. In the volcanism section, both are mentioned to have had volcanism in the early history of the Solar System. In the resurfacing section, both are mentioned to present a densely cratered surface. So I have the impression that Mercury scored one point for its deformation which, as the authors acknowledge, is due thermal contraction rather than internal convection.

In summary, both Mercury and the Moon are considered tectonically dead in terms of mantle convection, but the thermal contraction of Mercury triggers some kind of tectonic activity (reverse faulting) that is absent on the Moon.