Liquefaction-Induced Lateral Spreading at Izmit Bay During the Kocaeli (Izmit)-Turkey Earthquake
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UCLA UCLA Previously Published Works Title Liquefaction-Induced Lateral Spreading at Izmit Bay During the Kocaeli (Izmit)-Turkey Earthquake Permalink https://escholarship.org/uc/item/48z5w1pn Journal Journal of Geotechnical & Geoenvironmental Engineering, 130(12) Authors Cetin, K. Onder Youd, T Leslie Seed, Raymond B et al. Publication Date 2004 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Liquefaction-Induced Lateral Spreading at Izmit Bay During the Kocaeli (Izmit)-Turkey Earthquake K. Onder Cetin, M.ASCE1; T. Leslie Youd, M.ASCE2; Raymond B. Seed, M.ASCE3; Jonathan D. Bray, M.ASCE4; Jonathan P. Stewart, M.ASCE5; H. Turan Durgunoglu, M.ASCE6; W. Lettis, M.ASCE7; and M. Tolga Yilmaz8 Abstract: This paper presents a study of liquefaction-induced lateral ground displacements along the coast of Izmit Bay during the 1999 Kocaeli (Izmit)-Turkey earthquake. The paper discusses: (1) observed ground displacements after the earthquake, (2) the results of field investigations by means of borings and in situ index tests, including standard penetration tests, static cone penetration tests, and piezocone tests, (3) analyses of expected lateral displacements using two empirical models and one semiempirical model, and (4) comparisons between observed and calculated lateral ground movements. The three models provide inconsistent predictions of observed lateral ground displacements, with one method overpredicting and two methods both overpredicting and underpredicting observed lateral ground displacements by large amounts. Thus, it appears that there is a need for improved engineering tools for prediction of small to moderately significant lateral ground displacements (lateral displacements of approximately 0.1–2.5 m) at soil sites with similar ground characteris- tics to the case history sites presented herein. DOI: 10.1061/(ASCE)1090-0241(2004)130:12(1300) CE Database subject headings: Earthquakes; Liquefaction; Lateral displacement; Seismic hazard; Turkey; Bays. Introduction vestigations and in situ index tests including standard penetration tests (SPT), static cone penetration tests (CPT), and piezocone The 17 August 1999 Kocaeli-Turkey earthquake was an event of (CPTU) tests are discussed. These site investigation results are then used as a basis for calculation, by three analytical proce- magnitude Mw =7.4, and caused extensive liquefaction-induced ground displacements along the coast of Izmit Bay. This paper dures, of expected lateral ground displacements. Finally, a com- presents a study of the liquefaction-induced ground displacements parison is made between the observed ground displacements and observed at a number of sites; the police station, soccer field, the results of these three sets of ground displacement calculations. Degirmendere nose, and Yalova Harbor sites along the southern coast of Izmit Bay, as shown in Fig. 1. Within this paper’s con- fines, geologic setting and recorded ground motions at the soil Geologic Setting sites during the Kocaeli earthquake, the observed liquefaction- induced lateral ground displacements, and the results of site in- The Gulf of Izmit is situated in an east–west trending active gra- ben system which is dynamically affected by the interaction of the 1Associate Professor, Dept. of Civil Engineering, Middle East North Anatolian Fault zone and the Marmara Graben system. It is Technical Univ., 06531 Ankara, Turkey. bounded by two horsts: (1) Kocaeli Peninsula to the north and (2) 2Professor, Dept. of Civil and Environmental Engineering, Brigham the Armutlu Peninsula to the south, exhibiting completely differ- Young Univ., Provo, UT 84602. ent geomorphologic features, and by well defined fault scarps. 3Professor, Dept. of Civil and Environmental Engineering, Univ. of The graben, varying in the range of 6–10 km in width, is a com- California at Berkeley, Berkeley, CA 94720. paratively large, long and narrow basin filled with young sedi- 4 Professor, Dept. of Civil and Environmental Engineering, Univ. of ments of marine and continental facies (Seymen 1995). As shown California at Berkeley, Berkeley, CA 94720. in Fig. 2, the southern shores of Izmit Bay are covered by Ho- 5Associate Professor, Dept. of Civil and Environmental Engineering, locene deposits except a relatively small area, which was classi- Univ. of California, Los Angeles, CA 90095. 6Professor, Dept. of Civil Engineering, Bogazici Univ., 80815 Bebek, fied geologically as Bakacak formation of Companian- Istanbul, Turkey. Maastrihtien age consisting of marn, mudstone, conglomerate, 7William Lettis and Associates, Inc., Walnut Creek, CA 94596. and sandstone. From a sedimentalogical point of view, the south- 8Graduate Student Researcher, Dept. of Civil Engineering, Middle ern shores of Izmit Bay are covered principally by fine-grained East Technical Univ., 06531 Ankara, Turkey. sandy deposits which get finer (siltier and more clayey) towards Note. Discussion open until May 1, 2005. Separate discussions must the north into the depths of Izmit Bay. be submitted for individual papers. To extend the closing date by one month, a written request must be filed with the ASCE Managing Editor. The manuscript for this paper was submitted for review and possible publication on July 11, 2003; approved on February 16, 2004. This paper Ground Motions during 1999 Kocaeli Earthquake is part of the Journal of Geotechnical and Geoenvironmental Engineer- ing, Vol. 130, No. 12, December 1, 2004. ©ASCE, ISSN 1090-0241/ The Kocaeli (Izmit) earthquake occurred in northwestern Turkey 2004/12-1300–1313/$18.00. at 3:02 a.m. (local time) on August 17, 1999 along a 125 km 1300 / JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING © ASCE / DECEMBER 2004 Fig. 1. Case history site map segment of the North Anatolian Fault, as shown in Fig. 1. The tances are estimated approximately as 0.40g for the police station, ͑ ͒ earthquake Mw =7.4 generated a large number of ground-motion soccer field, and Degirmedere Nose sites and 0.30g for the Yalova recordings within 20 km of the fault rupture. Table 1 presents a Harbor site. In addition to available strong ground motion summary of select near fault strong ground-motion stations, and records, the results of one-dimensional equivalent linear site re- key characteristics of these records. Event-specific attenuation re- sponse studies performed using SHAKE-91 (Idriss and Sun 1992) lationships suggest that the peak horizontal ground acceleration led to the conclusion that the peak horizontal ground acceleration on a hypothetical “rock outcrop” and on soft soil at the police at these soil sites was on the order of 0.30–0.40g. The levels of station, soccer field, Degirmedere Nose, and Yalova Harbor sites, observed damage to the buildings and their contents at these sites located within a maximum of 2–3 Km from the fault rupture, also support this conclusion. would have been about 0.3–0.45g. Most conventional attenuation relationships available prior to the event tend to overpredict the observed near-field levels of shaking. However, if the attenuation relationship proposed by Abrahamson and Silva (1997) is scaled, Field Investigations on an event-specific local basis, using the near-field Izmit, Ya- rimca and Gebze station recordings, then the soft soil site peak Field investigations included rotary wash borings and in situ horizontal ground accelerations at about comparable fault dis- SPTs, CPTs, and CPTUs. A total of 10 SPT borings, 6 CPT, and 9 Fig. 2. Simplified geological map of Armutlu peninsula (after Goncuoglu et al. 1992): (1) Pamukova metamorphics, (2) sedimentary cover of Pamukova metamorphics (Triassic)(Ballikaya formation); (3) lower part of the İznik Metamorphics (Triassic); (4) Alicyayla limestone (Upper Triassic–Middle Jurassic); (5) upper part of the Iznik Metamorphics, ophiolitic metaolistostrome: black shading shows ophiolitic rocks (Upper Jurassic–Lower Cretaceous); (6) Bakacak formation (Campanian—Maastrichtian); (7) Incebel formation (Paleocene–Lutetian); (8) Sarisu volca- nics (Lutetian); (9) Fistikli granitoid (Eocene); (10) Kilinc formation (Sarmasiyan/Ponsian); (11) Pliocene detritals; and (12) recent deposits JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING © ASCE / DECEMBER 2004 / 1301 Table 1. Summary of Selected Main Shock Strong Motion Records (after Safak et al. 2000), Locations of Recording Stations Are Shown in Fig. 1. Peak horizontal acceleration (g) Station Distance to rupture Site Station coordinates plane (km) class Strong composition Weak composition Arcelik 40.830° N 17 Stiff 0.211 (W) 0.134 (S) (ARC) 29.360° E Soil Gebze 40.820° N 17 Stiff 0.144 (W) 0.266 (N) (GBZ) 29.440° E Soil Yarimca 40.763° N 4.4 Soft 0.262 (E) 0.298 (N) (YPT) 29.761° E Soil Izmit 40.790° N 7.7 Rock 0.226 (E) 0.169 (S) (IZT) 29.960° E Sakarya 40.737° N 3.3 Stiff 0.407 (E) N/A (S) (SKR) 30.384° E Soil CPTU soundings were performed at these sites. Standard penetra- indices (PIs) of the layer are 40–45 and 18–23, respectively. This tion tests were performed in close conformance with the guide- silty clay layer is underlain by a 1.5 m thick very loose to loose lines recommended by Seed et al. (1985), with direct driving silty sand layer. Below this layer there lies a soft and low plastic- energy measurements taken on some of the SPT tests. Cone pen- ity silty clay layer with LL and PI values of 37 and 17, respec- etration test and CPTUs were performed in conformance with tively. D6066-98 standards (ASTM 2000). A detailed presentation of in- dividual boring logs and other in situ test results will be discussed Observed Liquefaction-Induced Lateral Ground next, and is also available at ͗http://peer.berkeley.edu/turkey/ Displacements adapazari͘. At the police station site, mapped ground cracks due to lateral spreading were as wide as 0.64 m (Fig. 3). Ground displacements Ground Displacement Surveys continued to accrue with increased proximity to the shoreline, and lateral ground displacements reach to a total of about 2.4 m at the Due to possible caving of the fissure faces or simply stretching of shore of Izmit Bay along cross sections I, II, and III in Figs.