El and Bill
New member
As you know, there have been a number of major quakes in the past month - mostly around the 'ring of fire' surrounding the Pacific Ocean. There was another 7.2 quake in Chile this morning. Could these large quakes be associated and might they trigger more?
First off, there have been many 'after shocks' both in the Caribbean and along the Chilean coast. These are apparently associated with forces released by the initial big one, and then transferred along the major plate boundary fault or to ancilliary fault zones nearby. Such aftershocks have been extensively studied along active fault zones following past major earthquakes.
The San Andreas fault and many secondary and teritiary fault zones 'caused' by 'breakage' initiated by movement on the San Andreas have been mapped. These ancilliary faults often rift off the San Andreas (and the tertiary off the secondary) at predictable angles (predicted by physics from the fracturing of solids that are sheared along a lateral breakage of one big fracture). Following a quake on the San Andreas, these subsidiary faults often then must move to accomodate the movement of the San Andreas. Some of these resulting earthquakes are large and often 'snap' years after the big one on the San Andreas.
Secondly - and more into the world of speculation - could a major quake in Chile be 'responsible' for one in Indonesia (or Washington)? Frankly, we don't know.
As scientists we speculate (create hypotheses) and then must test these hypotheses to see if the results replicate. Testing, particularly with geologic ideas, can be difficult because of the scale of the subject and the (often) immense time periods required to replicate.
But both the scale and expanse of time can be an advantage to geologists - our data are 'stored' for us in rocks - all over the earth and through the 'storehouse' of great time.
Since I am no longer actively involved in earthquake research, I have been tapping into ol' buddies still active to pick their brains.
1. During periods of large earthquake activity, is there a greater possibility of a major quake in Seattle? Those I talked with would all publicly answer, "we don't know - we are actively researching this hypothesis." But, off the record, the hypotheses they are testing is "Yes. Seattle (or any location on major active fault zones) is more exposed now. The earth rings like a bell after a major quake, and energy is dispersed globally and could be 'the straw to break the camel's back' if energy is stored almost to the breaking point elsewhere. Or ... another hypothesis states crustal movement after a major quake causes movement and pressure to build up elsewhere and increases the probability of a distant quake (not simply an aftershock in close proximity to the initial quake). Highly accurate GPS locations in South America were shifted westerly anywhere from feet to inches (depending on distance from quake) after the initial Chilean quake.
2. So - we don't know if probabilities in Seattle are higher right now - but -since many of you are in active fault areas (coastal WA and OR and, of course, CA) it might be wise to read what to do if you feel an earth tremor:
http://earthquake.usgs.gov/prepare/
3. And, a topic particularly germane for us boaters, tsunami. This we have already discussed but can be reviewed at:
http://www.c-brats.com/viewtopic.php?t=1323&highlight=tsunami
First off, there have been many 'after shocks' both in the Caribbean and along the Chilean coast. These are apparently associated with forces released by the initial big one, and then transferred along the major plate boundary fault or to ancilliary fault zones nearby. Such aftershocks have been extensively studied along active fault zones following past major earthquakes.
The San Andreas fault and many secondary and teritiary fault zones 'caused' by 'breakage' initiated by movement on the San Andreas have been mapped. These ancilliary faults often rift off the San Andreas (and the tertiary off the secondary) at predictable angles (predicted by physics from the fracturing of solids that are sheared along a lateral breakage of one big fracture). Following a quake on the San Andreas, these subsidiary faults often then must move to accomodate the movement of the San Andreas. Some of these resulting earthquakes are large and often 'snap' years after the big one on the San Andreas.
Secondly - and more into the world of speculation - could a major quake in Chile be 'responsible' for one in Indonesia (or Washington)? Frankly, we don't know.
As scientists we speculate (create hypotheses) and then must test these hypotheses to see if the results replicate. Testing, particularly with geologic ideas, can be difficult because of the scale of the subject and the (often) immense time periods required to replicate.
But both the scale and expanse of time can be an advantage to geologists - our data are 'stored' for us in rocks - all over the earth and through the 'storehouse' of great time.
Since I am no longer actively involved in earthquake research, I have been tapping into ol' buddies still active to pick their brains.
1. During periods of large earthquake activity, is there a greater possibility of a major quake in Seattle? Those I talked with would all publicly answer, "we don't know - we are actively researching this hypothesis." But, off the record, the hypotheses they are testing is "Yes. Seattle (or any location on major active fault zones) is more exposed now. The earth rings like a bell after a major quake, and energy is dispersed globally and could be 'the straw to break the camel's back' if energy is stored almost to the breaking point elsewhere. Or ... another hypothesis states crustal movement after a major quake causes movement and pressure to build up elsewhere and increases the probability of a distant quake (not simply an aftershock in close proximity to the initial quake). Highly accurate GPS locations in South America were shifted westerly anywhere from feet to inches (depending on distance from quake) after the initial Chilean quake.
2. So - we don't know if probabilities in Seattle are higher right now - but -since many of you are in active fault areas (coastal WA and OR and, of course, CA) it might be wise to read what to do if you feel an earth tremor:
http://earthquake.usgs.gov/prepare/
3. And, a topic particularly germane for us boaters, tsunami. This we have already discussed but can be reviewed at:
http://www.c-brats.com/viewtopic.php?t=1323&highlight=tsunami
