Cooling of the K

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Cooling of the Kärdla Impact Crater Part II -
Impact and Geothermal Modeling

• Argo Jõeleht, Kalle Kirsimäe, Evelin Versh, Jüri
  Plado and Boris Ivanov

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Observation
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Impact modeling
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Geothermal modeling
Permeability structure
2 km
2 km
0
10-14 - 10-19 m2
10-12 - 10-17 m2
2 km
2 km
10-12
10-19 m2
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Moderate permeability case
40 years
Initial state
0
1.5 km
1.5 km
1.5 km
1.5 km
Darcy velocity in m/s or kg/year
450
20C
163
307
1.E-7
3.E3
1.E-12
3.E-2
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Higher permeability case
1.5 years
Initial state
0
1.5 km
1.5 km
1.5 km
1.5 km
Darcy velocity in m/s or kg/year
450
20C
163
307
1.E-7
3.E3
1.E-12
3.E-2
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300 m from the centre (approximate location of
K-18)
Moderately convective case
Purely conductive case
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700 m from the centre (approximate location of
K-12)
Moderately convective case
Purely conductive case
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Moderate permeability case
5000 years
0
1.5 km
1.5 km
1.5 km
1.5 km
Darcy velocity in m/s or kg/year
75
20C
38
57
10-10
3
10-15
310-5
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Conclusions

• Numerical simulations confirm existence of
  hydrothermal system in Kärdla
• Cooling to boiling point temperature was a matter
  of years to a few hundred years
• Free convection ceased in less than 5000 years
• Cooling of rim wall requires detailed 3D modeling