Table 1 Comparison of three earthquakes triggered by open pit mining
|
|
Wappingers Falls, New York, USA |
Belchatow, Central Poland |
Cacoosing Valley, Pennsylvania, USA |
|---|---|---|---|
|
Date |
07 June 1974 |
29 November 1980 |
16 January 1994 |
|
Location |
+41.62°, –073.94° |
~ +51.3°, ~ –019.5° |
+40.37°, –076.07° |
|
Depth (km) |
~11 |
~31? |
2.0±1.02 |
|
Magnitude |
3.3 (mb, Nuttli) |
4.6 ML |
4.6 mb(Lg) |
|
Max. Intensity |
MMI V |
MSK 6-7 ≈ MMI |
MMI VI-VII |
|
Damage |
2 broken windows |
'spectacular'(?) |
~US$2 million |
|
Felt Distance (km) |
10 |
100 |
~50 |
|
Mechanism |
thrust |
reverse, oblique |
reverse, left-lateral |
|
Mine Type |
limestone |
brown coal |
carbonates |
|
Open Pit Size (km) |
1 x 1 x 0.025 |
1 x 2 x 0.1 |
0.5 x 0.5 x 0.015 |
|
Overburden (m) |
none |
100 |
none |
|
Faults |
none aligned |
graben3 |
no, but many joints |
|
Pore Pressure |
not discussed |
water withdrawal |
flooded |
|
Stress-change (MPa) |
0.74 |
2.54 |
0.135 |
Notes 1. Depths estimated from aftershock/foreshocks.
2. Depth determined from broadband waveform modelling.
3. Kleszczow Graben has been intermittently active throughout the Cenozoic (van Loon 2002).
4. Triggering stress decrease caused by unloading.
5. Triggering Coulomb stress increase.