| Abstract: | Interaction of the elastic lithosphere with the underlying anelastic asthenosphere causes strain to propagate along the Earth‘s surface in a diffusion-like manner following tectonism at plate boundaries. This process transfers stress between adjacent tectonic segments and influences the temporal tectonic pattern along a plate boundary. Observations of such strain transients have been rare, and have hitherto been confined to strike-slip and underthrusting plate boundaries1. Here we report the observation of a strain transient at the divergent (spreading) plate boundary in Iceland. A Global Positioning System survey undertaken a decade after an episode of dyke intrusion accompanying several metres of crustal spreading reveals a spatially varying strain field with the expected diffusion-pulse shape and an amplitude three times greater than the 5.7 cm that would be expected from the average spreading rate2. A simple one-dimensional model with a thin elastic layer overlying a viscous layer fits the data well and yields a stress diffusivity of 1.1 ?? 0.3 m2 s-1. Combined with struc-tural information from magnetotelluric measurements, this implies a viscosity of 0.3-2 ?? 1019 Pa s - a value comparable to that derived for Iceland from post-glacial rebound23, but low compared with estimates for mantle viscosity obtained elsewhere3. |
| Genre: | Article |
| ProdID: | 70017153 |
| Citation Author: | Foulger, G. R.; Jahn, C. -H.; Seeber, G.; Einarsson, P.; Julian, B. R.; Heki, K. |
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| Citation End Page: | 490 |
| Citation Issue: | 6386 |
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| Citation Language: | English |
| Citation Larger Work Title: | Nature |
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| Citation Number Of Pages: | 3 |
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| Citation Search Results Text: | Post-rifting stress relaxation at the divergent plate boundary in Northeast Iceland; 1992; Article; Journal; Nature; Foulger, G. R.; Jahn, C. -H.; Seeber, G.; Einarsson, P.; Julian, B. R.; Heki, K. |
| Citation Start Page: | 488 |
| Citation Volume: | 358 |
| Citation Year: | 1992 |
| Type: | citation/reference |
| Text: | Post-rifting stress relaxation at the divergent plate boundary in Northeast Iceland; 1992; Article; Journal; Nature; Foulger, G. R.; Jahn, C. -H.; Seeber, G.; Einarsson, P.; Julian, B. R.; Heki, K. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 1 Jan 1992 00:00 -0600 |
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