Post by Deleted on May 30, 2015 11:11:12 GMT -6
Okay, this is coming a bit late, but in reading about this specific quake, it has become more interesting to share than simply saying 'Hey! Another quake happened!'. There is a bit more to this...
(Source)
That may be a slightly different map than what you normally see in media but it shows reported feeling and experience at distances. This happened well 'out there', and so, it wasn't damaging (The 'Pager' or damage estimate system was green for this one) but it was felt.
What made me wonder a bit is that this IS out there a good distance and not near the titanic meeting points of the Pacific and Eurasian tectonic plates. Interior quakes are always interesting ones (like New Madrid, in the US).
Source (emphasis on interesting points)
This one was over 600km for depth. Wayyy down there. What I also found interesting was a detail too small to cover in the geology 101 course I just went through, but quite interesting to see in my opinion. The giant plates of Eurasia and the Pacific have a wee little one between them.
PDF Map of the Tectonic Region
(Same USGS source page)
To look at the map, it makes more sense for location and how things like distortion of plates happen. Convergence also means the plates are in conflict, moving together....from all sides? That is one stressful plate border area all around.
Anyway.. I thought I'd share a little I found on this and how it was a bit different than many we see regularly these days.
(Source)
That may be a slightly different map than what you normally see in media but it shows reported feeling and experience at distances. This happened well 'out there', and so, it wasn't damaging (The 'Pager' or damage estimate system was green for this one) but it was felt.
What made me wonder a bit is that this IS out there a good distance and not near the titanic meeting points of the Pacific and Eurasian tectonic plates. Interior quakes are always interesting ones (like New Madrid, in the US).
The May 30, 2015 M7.8 earthquake WNW of Chichi-shima, Japan occurred as the result of oblique-normal faulting at a depth of over 660 km beneath the Pacific Ocean. The earthquake is located within the interior of the Pacific plate that subducts beneath Japan starting at the Izu trench, several hundred kilometers to the east of the event (and at the surface of the Earth). At the location of the earthquake, the Pacific plate moves approximately westwards with respect to the Philippine Sea plate at a rate of 39 mm/yr. This earthquake occurred in response to stresses generated by the slow distortion of the Pacific plate at depth, rather than occurring on the interface between the Pacific plate and the overriding Philippine Sea plate.
Earthquakes that have focal depths greater than 300 km are commonly termed "deep-focus". Deep-focus earthquakes cause less damage on the earth’s surface above their foci than is the case with similar magnitude shallow-focus earthquakes. Large deep-focus earthquakes may be felt at great distance from their epicenters. The largest recorded deep-focus earthquake was a 2013 M 8.3 earthquake that occurred at a depth of 600 km within the subducted Pacific plate beneath the Sea of Okhotsk, offshore northeastern Russia. The M 8.3 Okhotsk earthquake was felt all over Asia, as far away as Moscow, and across the Pacific along the western seaboard of the United States. Over the past century, 66 earthquakes with a magnitude of M7 or more have occurred at depths greater than 500 km; three of these were located in the same region as today's event. The largest nearby event at these depths was a 1968 M 7.3 earthquake, several hundred kilometers to the south of this earthquake.
Earthquakes that have focal depths greater than 300 km are commonly termed "deep-focus". Deep-focus earthquakes cause less damage on the earth’s surface above their foci than is the case with similar magnitude shallow-focus earthquakes. Large deep-focus earthquakes may be felt at great distance from their epicenters. The largest recorded deep-focus earthquake was a 2013 M 8.3 earthquake that occurred at a depth of 600 km within the subducted Pacific plate beneath the Sea of Okhotsk, offshore northeastern Russia. The M 8.3 Okhotsk earthquake was felt all over Asia, as far away as Moscow, and across the Pacific along the western seaboard of the United States. Over the past century, 66 earthquakes with a magnitude of M7 or more have occurred at depths greater than 500 km; three of these were located in the same region as today's event. The largest nearby event at these depths was a 1968 M 7.3 earthquake, several hundred kilometers to the south of this earthquake.
This one was over 600km for depth. Wayyy down there. What I also found interesting was a detail too small to cover in the geology 101 course I just went through, but quite interesting to see in my opinion. The giant plates of Eurasia and the Pacific have a wee little one between them.
PDF Map of the Tectonic Region
The Philippine Sea plate is bordered by the larger Pacific and Eurasia plates and the smaller Sunda plate. The Philippine Sea plate is unusual in that its borders are nearly all zones of plate convergence.
To look at the map, it makes more sense for location and how things like distortion of plates happen. Convergence also means the plates are in conflict, moving together....from all sides? That is one stressful plate border area all around.
Anyway.. I thought I'd share a little I found on this and how it was a bit different than many we see regularly these days.