A first approach to earthquake damage estimation in Haiti: advices to minimize the seismic risk

This study is in the frame of the cooperative line that several Spanish Universities and other foreign partners started with the Haitian government in 2010. According to our studies (Benito et al. in An evaluation of seismic hazard in La Hispaniola, after the 2010 Haiti earthquake, 33rd General Assembly of the European Seismological Commission, Moscow, Russia, 2012) and recent scientific literature, the earthquake hazard in Haiti remains high (Calais et al. in Nat Geosci 3:794–799, 2010). In view of this, we wonder whether the country is currently ready to face another earthquake. In this sense, we estimated several damage scenarios in Port-au-Prince and Cap-Haitien associated to realistic possible major earthquakes. Our findings show that almost 50 % of the building stock of both cities would result uninhabitable due to structural damage. Around 80 % of the buildings in both cities have reinforced concrete structure with concrete block infill; however, the presence of masonry buildings becomes significant (between 25 and 45 % of the reinforced concrete buildings) in rural areas and informal settlements on the outskirts, where the estimated damage is higher. The influence of the soil effect on the damage spatial distribution is evident in both cities. We have found that the percentage of uninhabitable buildings in soft soil areas may be double the percentage obtained in nearby districts located in hard soil. These results reveal that a new seismic catastrophe of similar or even greater consequences than the 2010 Haiti earthquake might happen if the earthquake resilience is not improved in the country. Nowadays, the design of prevention actions and mitigation policies is the best instrument the society has to face seismic risk. In this sense, the results of this research might contribute to define measures oriented to earthquake risk reduction in Haiti, which should be a real priority for national and international institutions.

John Winthrop's proposal respecting electrical globes and jars, ca. 1758

In this proposal, John Winthrop explains the need to replace damaged "electric globes" used in the College's collection of scientific apparatus. He states that Benjamin Franklin, at the time residing in London, was willing to seek replacement globes for the College's collection. Winthrop then proceeds to assert that the College should acquire "square bottles, of a moderate size, fitted in a wooden box, like what they call case bottles for spirits" instead of the large jars included in the scientific apparatus, because those jars cracked frequently.

San Francisco, California, Earthquake and Fire, 1906 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: [San Francisco, California, showing the area destroyed by fire, April 18-21, 1906]. It was published by R.J. Waters & Co. in 1906. Scale [ca. 1:21,000]. Covers the northeastern portion of the city showing burnt district in red. The image inside the map neatline is georeferenced to the surface of the earth and fit to the California Zone III State Plane Coordinate System NAD83 (in Feet) (Fipszone 0403). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as the burnt district, roads, drainage, selected public buildings, wharves, and more. Relief shown by contours. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Controlo fuzzy semi-activo para aparelhos de amortecimento variável na protecção sísmica

Trabalho apresentado no 10º Congresso Nacional de Sismologia e Engenharia Sísmica, 20-22 abril de 2016, Ponta Delgada, Açores, Portugal

Application of the Equivalent Static Analysis method to the design of a steel frame structure with added viscous dampers

All the structures designed by engineers are vulnerable to natural disasters including floods and earthquakes. The energy released during strong ground motions should be dissipated by structural elements. Before 1990’s, this energy was expected to be dissipated through the beams and columns which at the same time were a part of gravity-load-resisting system. However, the main disadvantage of this idea was that gravity-resisting-frame was not repairable. Hence, during 1990’s, the idea of designing passive energy dissipation systems, including dampers, emerged. At the beginning, main problem was lack of guidelines for passive energy dissipation systems. Although till 2000 many guidelines and procedures where published, yet most of them were based on complicated analysis which was not so convenient for engineers and practitioners. In order to solve this problem recently some alternative design methods are proposed including 1. Lopez Garcia (2001) simple procedure for optimal damper configuration in MDOF structures 2. Christopoulos and Filiatrault (2006) trial and error procedure 3. Silvestri et al. (2010) Five-Step Method. 4. Palermo et al. (2015) Direct Five-Step Method. 5. Palermo et al. (2016) Simplified Equivalent Static Analysis (ESA). In this study, effectiveness and differences between last three alternative methods have been evaluated.

(Table 1) AMS radiocarbon ages from ODP Sites 169-1033 and 169-1034

This paper explores the paleoseismic record potentially preserved in the upper 40 m of hydraulic piston cores collected in 1996 at two sites in Saanich Inlet, British Columbia, during ocean drilling program (ODP) Leg 169S. The ODP cores are missing 1-2 m of water-rich sediment directly underlying the seafloor, but this sediment is preserved in shorter piston cores collected in 1989 and 1991. The upper part of the ODP cores consists of rhythmically laminated (varved) marine mud with intercalated massive beds, interpreted to be debris flow deposits. Some of the debris flow deposits are linked to past earthquakes, including the 1946 Vancouver Island earthquake (M7.2), a great (M8-9) plate-boundary earthquake at the Cascadia subduction zone in January 1700, and a large crustal or plate-boundary earthquake about 1000 yr ago. Earthquakes may also be responsible for debris flows in about AD 1600, 1500, 1250, 1150, 850, 450, 350, 180, and BC 200, 220, 500, 900, and 1050. If so, the average recurrence interval for moderate to large earthquakes, which trigger debris flows in Saanich Inlet, is about 150 yr. This recurrence interval is broadly consistent with the frequency of moderate to large earthquakes in the region during the historical period. Debris flows, however, can also be triggered by non-seismic processes, making it difficult to assemble a complete earthquake record from the Saanich Inlet cores. We propose that extensive debris flow deposits, emplaced by single large failures or many smaller coincident failures, probably have a seismic origin.

(Table 1) Experimental shear strength values for IODP Exp315 and Exp316 holes

We investigate the mechanics of slope failures on the Nankai accretionary complex offshore Japan in the vicinity of a major out-of-sequence thrust fault (termed the "megasplay"). Incorporating laboratory-measured shear strength of slope sediments sampled during Integrated Ocean Drilling Project (IODP) Expeditions 315 and 316 with local seafloor slope angles from bathymetric data and constraints on in-situ effective stress conditions from drilling, we find that slopes in the study area are stable and submarine landslides are not expected to occur under static conditions. In order to assess the possibility of slope failure triggered by coseismic rupture of the megasplay fault, we use empirical relations for strong ground motion attenuation from earthquakes with Mw 6-9. We find that the slope sediments should be stable based on computations from one model, developed from a catalog of worldwide subduction zone earthquakes (Youngs et al., 1997, doi:10.1785/gssrl.68.1.58). However, using a different model developed primarily from a catalog of crustal earthquakes in Japan (Kanno et al., 2006, doi:10.1785/0120050138), we find that slopes should be unstable for earthquakes 8 <= Mw <= 9, and possibly unstable for events with 6 <= Mw < 8, depending on the proximity of rupture to the seafloor. Considering limitations of the models and geologic observations of slope failure recurrence, the true slope stability is likely to be in between the predictions of the two models, and we suggest that it may be modulated by long-term pore pressure fluctuations.

Total organic carbon, metal concentrations and metal and aluminium ratios in bulk sediment from the ODP sample 169-1033B-4H-4,54-74

Holocene laminated sediments in Saanich Inlet, British Columbia, are interrupted by frequent, non-laminated, massive layers. These layers may be debris flows released by earthquakes or bioturbated sediments deposited during periods of relatively high bottom water oxygen concentration and/or low surface productivity, or both. We determined the organic carbon content and the concentration of a suite of redox-sensitive metals in bulk sediments at approximately 1-cm resolution across a laminated-massive-laminated interval (ODP Leg 169S Sample 1033B-4H-4,54-74), to determine the redox conditions under which the massive layer was deposited. Our results indicate that this massive interval was deposited under anoxic bottom waters. Manganese/Al ratios are consistently low throughout the massive section, while Mo/Al, Cd/Al, Re/Al, and U/Al ratios are enriched relative to their metal/Al ratios in detrital material (represented by Cowichan River suspended sediments). The concentration of organic carbon in the lower portion of the massive layer is higher than in the upper portion, which has a concentration similar to that in the overlying and underlying laminated sediments. Well-defined peaks in Mo/Al, Cd/Al, and Re/Al and a broad peak in U/Al occur in the lower portion of the massive layer. The positions of the Cd/Al, Re/Al, and Mo/Al peaks, as well as the increase in organic carbon content with depth in the massive layer, are best explained by a process of diagenetic redistribution of metals that occurred after the massive layer was emplaced.

(Table 1) Sr-isotope values of representative sediment samples from ODP sites at the Costa Rica margin

Two sealed borehole hydrologic observatories (CORKs) were installed in two active hydrogeochemical systems at the Costa Rica subduction zone to investigate the relationship between tectonics, fluid flow, and fluid composition. The observatories were deployed during Ocean Drilling Program (ODP) Leg 205 at Site 1253, ~ 0.2 km seaward of the trench, in the upper igneous basement, and at Site 1255, ~ 0.5 km landward of the trench, in the décollement. Downhole instrumentation was designed to monitor formation fluid flow rates, composition, pressure, and temperature. The two-year records collected by this interdisciplinary effort constitute the first co-registered hydrological, chemical, and physical dataset from a subduction zone, providing critical information on the average and transient state of the subduction thrust and upper igneous basement. The continuous records at ODP Site 1253 show that the uppermost igneous basement is highly permeable hosting an average fluid flow rate of 0.3 m/yr, and indicate that the fluid sampled in the basement is a mixture between seawater (~ 50%) and a subduction zone fluid originating within the forearc (~ 50%). These results suggest that the uppermost basement serves as an efficient pathway for fluid expelled from the forearc that should be considered in models of subduction zone hydrogeology and deformation. Three transients in fluid flow rates were observed along the décollement at ODP Site 1255, two of which coincided with stepwise increases in formation pressure. These two transients are the result of aseismic slip dislocations that propagated up-dip from the seismogenic zone over the course of ~ 2 weeks terminating before reaching ODP Site 1255 and the trench. The nature and temporal behavior of strain and the associated hydrological response during these slow slip events may be an analog for the response of the seaward part of the subduction prism during or soon after large subduction zone earthquakes.

Grain size distribution analysis of prominent beds on Southern Central Chilean seamounts

Gravity cores obtained from isolated seamounts located within, and rising up to 300 m from the sediment-filled Peru-Chile Trench off Southern Central Chile (36°S-39°S) contain numerous turbidite layers which are much coarser than the hemipelagic background sedimentation. The mineralogical composition of some of the beds indicates a mixed origin from various source terrains while the faunal assemblage of benthic foraminifera in one of the turbidite layers shows a mixed origin from upper shelfal to middle-lower bathyal depths which could indicate a multi-source origin and therefore indicate an earthquake triggering of the causing turbidity currents. The bathymetric setting and the grain size distribution of the sampled layers, together with swath echosounder and sediment echosounder data which monitor the distribution of turbidites on the elevated Nazca Plate allow some estimates on the flow direction, flow velocity and height of the causing turbidity currents. We discuss two alternative models of deposition, both of which imply high (175-450 m) turbidity currents and we suggest a channelized transport process as the general mode of turbidite deposition. Whether these turbidites are suspension fallout products of thick turbiditic flows or bedload deposits from sheet-like turbidity currents overwhelming elevated structures cannot be decided upon using our sedimentological data, but the specific morphology of the seamounts rather argues for the first option. Oxygen isotope stratigraphy of one of the cores indicates that the turbiditic sequences were deposited during the last Glacial period and during the following transition period and turbiditic deposition stopped during the Holocene. This climatic coupling seems to be dominant, while the occurrence of megathrust earthquakes provides a trigger mechanism. This seismic triggering takes effect only during times of very high sediment supply to the shelf and slope.

Plan de reconstrucción 1971-1973 de las provincias de Coquimbo, Aconcagua, Santiago, Valparaíso y O'Higgins, afectados por el sismo del 8 de julio de 1971.

Mode of access: Internet.

Auxilios a los damnificados por el terremoto de Cuilapa

Mode of access: Internet.

Guatemala earthquake : hearing before the Subcommittee on Western Hemisphere Affairs and Subcommittee on Foreign Assistance of the Committee on Foreign Relations, United States Senate, Ninety-fourth Congress, second session ... February 16, 1976.

Mode of access: Internet.

Abatement of seismic hazards to lifelines : action plan /

BSSC Program on Improved Seismic Safety Provisions.

Indien, Das Schwer-Heimgesuchte Reich : Das Buch enthält eine vollständige Beschreibung der Pest, Teurung und des Erdbebens von 1896-97 ; Einschliesslich einer genauen Beschreibung der Linderungs-Arbeit durch die "Home and Foreign Relief Commission.' [!] /

"Verschönert mit vielen Abbildungen, welche die wirklichen Begebenheiten in Verbindung mit der Hungersnot, der Pest, dem Erdbeben und der Linderungsarbeit darstellen."