NORTH YEMEN EARTHQUAKE NORTH YEMEN EARTHQUAKE

IN 13/DEC/1982IN 13/DEC/1982BY GEORGE PLAFKER, ROBERT AGAR, A. H. ASKER, AND M. HANIF

PRESENTED BY :

ABDULLAH DAWOOD MOUSA

Date : 13 Dec 1982

Latitude : 14.95

Longitude : 44.95

Magnitude : 6.0 Mb

Depth : 7 km as estimated by Choy and Kind (1987)

No. of deaths : 1700 to 2500

Maximum Mercalli Intensity : VII to VIII

FIG. 1. Plate tectonic setting of 13 December 1982 North Yemen earthquake showing major lateCenozoic volcanic fields (stippled), plate boundaries (dashed lines), and relative motions in millimeters/year between the Arabia plate and the Nubia, Somalia, and Danakil plates. From Le Pichon and Francheteau (1978) and Coleman and McGuire (1987).

FIG. 2. Geologic map of the Yemen Plateau region showing distribution of major faults .From Grolier and Overstreet (1978) and Coleman andMcGuire (1987).

FIG. 3. Schematic crustal section along east-west line through Sana and Marib (Figure 2) showing suggested mechanism for extension-related volcanism and seismicity resulting from decoupling of western part of Arabia plate from mantle along an eastward-dipping detachment fault. Open arrows indicate motion of crust and mantle relative to Red Sea spreading axis; paired arrows indicate relative motion across faults. Quaternary volcanic centers are inferred to be localized along deep transcurrent faults andgraben-bounding normal faults within extending crust. Earthquakes may occur on intracrustal fractures and along the detachment fault at the base of the crust. Crustal thickness and composition are assumed to be comparable to those of southern Saudi Arabia (Mooney et al., 1985; Gettings et al., 1986). Novertical exaggeration.

FIG. 4. Map of south-central Yemen Arab Republic showing location of linear Area of map shown in Figure 2.

FIG. 5. (A) View north-northwest along continuous zigzag linear tectonic crack (arrows) having abouta 1 to 2 cm extension. Crack has an overall 330 ° trend consisting of long segments trending 325 ° andshorter segments trending 355 °. (B) Close-up view of crack in foreground of (A). Location is less than 2km from earthquake

FIG. 9. View of south-southeast along continuous single linear crack in fine loose sand that haswidened surface crack by sloughing into it.

FIG. Map of south-central Yemen Arab Republic showing highly generalized isoseismal linesbased on Modified Mercalli scale.

FlG. 12. Aerial view of typical damage to mud-brick construction at Risabah, 6 km west-northwestof earthquake epicenter .

FIG. Contrast of earthquake effects to reinforced concrete frame building. Location in Shanadib, 9.5 kmnorth-northwest of main shock epicenter.

One of several prefabricated wood-frame housing units on post foundations at DhamarAgricultural Center 9 km west-northwest of earthquake epicenter (Figure 11).

FIG. 16. Linear ground crack as wide as 20 cm at Himyarite archaeological site near Marib, 130 kmnortheast of epicentral region

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