| Abstract: | The presence of raised beaches and marine terraces along the Makran coast indicates episodic uplift of the continental margin resulting from large-magnitude earthquakes. The uplift occurs as incremental steps similar in height to the 1-3 m of measured uplift resulting from the November 28, 1945 (M 8.3) earthquake at Pasni and Ormara, Pakistan. The data support an E-W-trending, active subduction zone off the Makran coast. The raised beaches and wave-cut terraces along the Makran coast are extensive with some terraces 1-2 km wide, 10-15 m long and up to 500 m in elevation. The terraces are generally capped with shelly sandstones 0.5-5 m thick. Wave-cut cliffs, notches, and associated boulder breccia and swash troughs are locally preserved. Raised Holocene accretion beaches, lagoonal deposits, and tombolos are found up to 10 m in elevation. The number and elevation of raised wave-cut terraces along the Makran coast increase eastward from one at Jask, the entrance to the Persian Gulf, at a few meters elevation, to nine at Konarak, 250 km to the east. Multiple terraces are found on the prominent headlands as far east as Karachi. The wave-cut terraces are locally tilted and cut by faults with a few meters of displacement. Long-term, average rates of uplift were calculated from present elevation, estimated elevation at time of deposition, and 14C and U-Th dates obtained on shells. Uplift rates in centimeters per year at various locations from west to east are as follows: Jask, 0 (post-Sangamon); Konarak, 0.031-0.2 (Holocene), 0.01 (post-Sangamon); Ormara 0.2 (Holocene). ?? 1979. |
| Genre: | Article |
| ProdID: | 70012441 |
| Citation Author: | Page, W. D.; Alt, J. N.; Cluff, L. S.; Plafker, G. |
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| Citation End Page: | 547 |
| Citation Issue: | 1-4 |
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| Citation Language: | English |
| Citation Larger Work Title: | Tectonophysics |
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| Citation Number Of Pages: | 15 |
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| Citation Search Results Text: | Evidence for the recurrence of large-magnitude earthquakes along the Makran coast of Iran and Pakistan; 1979; Article; Journal; Tectonophysics; Page, W. D.; Alt, J. N.; Cluff, L. S.; Plafker, G. |
| Citation Start Page: | 533 |
| Citation Volume: | 52 |
| Citation Year: | 1979 |
| Type: | citation/reference |
| Text: | Evidence for the recurrence of large-magnitude earthquakes along the Makran coast of Iran and Pakistan; 1979; Article; Journal; Tectonophysics; Page, W. D.; Alt, J. N.; Cluff, L. S.; Plafker, G. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Mon, 1 Jan 1979 00:00 -0600 |
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