GEOLOGIC HAZARDS Chapter 8
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International Society for Soil Mechanics and Geotechnical Engineering
INTERNATIONAL SOCIETY FOR SOIL MECHANICS AND GEOTECHNICAL ENGINEERING This paper was downloaded from the Online Library of the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE). The library is available here: https://www.issmge.org/publications/online-library This is an open-access database that archives thousands of papers published under the Auspices of the ISSMGE and maintained by the Innovation and Development Committee of ISSMGE. CASE STUDY AND FORENSIC INVESTIGATION OF LANDSLIDE AT MARDOL IN GOA Leonardo Souza,1 Aviraj Naik,1 Praveen Mhaddolkar,1 and Nisha Naik2 1PG student – ME Foundation Engineering, Goa College of Engineering, Farmagudi Goa; [email protected] 2Associate Professor – Civil Engineering Department, Goa College of Engineering, Farmagudi Goa; [email protected] Keywords: Forensic Investigations, Landslides, Slope Failure Abstract: Goa, like the rest of India is undergoing an infrastructure boom. Many infrastructure works are carried out on hill sides in Goa. As a result there is a lot of hill cutting activity going on in Goa. This has caused major landslides in many parts of Goa leading to damage and loss of property and the environment. Forensic analysis of a failure can significantly reduce chances of future slides. The primary purpose of post failure slope and stability analysis is to contribute to the safe and economic planning for disaster aversion. Western Ghats (also known as Sahyadri) is a mountain range that runs along the west coast of India. Most of Goa's soil cover is made up of laterites rich in ferric-aluminium oxides and reddish in colour. Although such laterite composition exhibit good shear strength properties, hills composing of soil possessing low shear strength are also found at some parts of the state. -
2021 Oregon Seismic Hazard Database: Purpose and Methods
State of Oregon Oregon Department of Geology and Mineral Industries Brad Avy, State Geologist DIGITAL DATA SERIES 2021 OREGON SEISMIC HAZARD DATABASE: PURPOSE AND METHODS By Ian P. Madin1, Jon J. Francyzk1, John M. Bauer2, and Carlie J.M. Azzopardi1 2021 1Oregon Department of Geology and Mineral Industries, 800 NE Oregon Street, Suite 965, Portland, OR 97232 2Principal, Bauer GIS Solutions, Portland, OR 97229 2021 Oregon Seismic Hazard Database: Purpose and Methods DISCLAIMER This product is for informational purposes and may not have been prepared for or be suitable for legal, engineering, or surveying purposes. Users of this information should review or consult the primary data and information sources to ascertain the usability of the information. This publication cannot substitute for site-specific investigations by qualified practitioners. Site-specific data may give results that differ from the results shown in the publication. WHAT’S IN THIS PUBLICATION? The Oregon Seismic Hazard Database, release 1 (OSHD-1.0), is the first comprehensive collection of seismic hazard data for Oregon. This publication consists of a geodatabase containing coseismic geohazard maps and quantitative ground shaking and ground deformation maps; a report describing the methods used to prepare the geodatabase, and map plates showing 1) the highest level of shaking (peak ground velocity) expected to occur with a 2% chance in the next 50 years, equivalent to the most severe shaking likely to occur once in 2,475 years; 2) median shaking levels expected from a suite of 30 magnitude 9 Cascadia subduction zone earthquake simulations; and 3) the probability of experiencing shaking of Modified Mercalli Intensity VII, which is the nominal threshold for structural damage to buildings. -
Recommended Guidelines for Liquefaction Evaluations Using Ground Motions from Probabilistic Seismic Hazard Analyses
RECOMMENDED GUIDELINES FOR LIQUEFACTION EVALUATIONS USING GROUND MOTIONS FROM PROBABILISTIC SEISMIC HAZARD ANALYSES Report to the Oregon Department of Transportation June, 2005 Prepared by Stephen Dickenson Associate Professor Geotechnical Engineering Group Department of Civil, Construction and Environmental Engineering Oregon State University ODOT Liquefaction Hazard Assessment using Ground Motions from PSHA Page 2 ABSTRACT The assessment of liquefaction hazards for bridge sites requires thorough geotechnical site characterization and credible estimates of the ground motions anticipated for the exposure interval of interest. The ODOT Bridge Design and Drafting Manual specifies that the ground motions used for evaluation of liquefaction hazards must be obtained from probabilistic seismic hazard analyses (PSHA). This ground motion data is routinely obtained from the U.S. Geologocal Survey Seismic Hazard Mapping program, through its interactive web site and associated publications. The use of ground motion parameters derived from a PSHA for evaluations of liquefaction susceptibility and ground failure potential requires that the ground motion values that are indicated for the site are correlated to a specific earthquake magnitude. The individual seismic sources that contribute to the cumulative seismic hazard must therefore be accounted for individually. The process of hazard de-aggregation has been applied in PSHA to highlight the relative contributions of the various regional seismic sources to the ground motion parameter of interest. The use of de-aggregation procedures in PSHA is beneficial for liquefaction investigations because the contribution of each magnitude-distance pair on the overall seismic hazard can be readily determined. The difficulty in applying de-aggregated seismic hazard results for liquefaction studies is that the practitioner is confronted with numerous magnitude-distance pairs, each of which may yield different liquefaction hazard results. -
5.4.5 Geological Hazards
Section 5.4.5: Risk Assessment – Geological Hazards 5.4.5 Geological Hazards The following section provides the hazard profile (hazard description, location, extent, previous occurrences and losses, probability of future occurrences, and impact of climate change) and vulnerability assessment for the geological hazards in Sussex County. 2016 Plan Update Changes The hazard profile has been significantly enhanced to include a detailed hazard description, location, extent, previous occurrences, probability of future occurrence, and potential change in climate and its impacts on the geological hazards is discussed. The geological hazards is now located in Section 5 of the plan update. It includes landslide, land subsidence and sinkholes, all of which were profiled separately in the 2011 HMP. New and updated figures from federal and state agencies are incorporated. U.S. 2010 Census data was incorporated, where appropriate. Previous occurrences were updated with events that occurred between 2008 and 2015. A vulnerability assessment was conducted for the geological hazards and it now directly follows the hazard profile. 5.4.5.1 Profile Hazard Description Geological hazards are any geological or hydrological processes that pose a threat to humans and natural properties. Every year, severe natural events destroy infrastructure and cause injuries and deaths. Geologic hazards may include volcanic eruptions and other geothermal related features, earthquakes, landslides and other slope failures, mudflows, sinkhole collapses, snow avalanches, flooding, glacial surges and outburst floods, tsunamis, and shoreline movements. For the purpose of this HMP update, only landslides and land subsidence/sinkholes will be discussed in the Geological Hazard profile. Landslides According to the U.S. -
1. Geology and Seismic Hazards
8 PUBLIC SAFETY ELEMENT As required by State law, the Public Safety Element addresses the protection of the community from unreasonable risks from natural and manmade haz- ards. This Element provides information about risks in the Eden Area and delineates policies designed to prepare and protect the community as much as possible from the effects of: ♦ Geologic hazards, including earthquakes, ground-shaking, liquefaction and landslides. ♦ Flooding, including dam failures and inundation, tsunamis and seiches. ♦ Wildland fires. ♦ Hazardous materials. This Element also contains information and policies regarding general emer- gency preparedness. Each section includes background information on the particular hazard followed by goals, policies and actions designed to minimize risk for Eden Area residents. The Public Safety Element establishes mechanisms to prepare for and reduce death, injuries and damage to property from public safety hazards like flood- ing, fires and seismic events. Hazards are an unavoidable aspect of life, and the Public Safety Element cannot eliminate risk completely. Instead, the Element contains policies to create an acceptable level of risk. 1. GEOLOGY AND SEISMIC HAZARDS Earthquakes and secondary seismic hazards such as ground-shaking, liquefac- tion and landslides are the primary geologic hazards in the Eden Area. This section provides background on the seismic hazards that affect the Eden Area and includes goals, policies and actions to minimize these risks. 8-1 COUNTY OF ALAMEDA EDEN AREA GENERAL PLAN PUBLIC SAFETY ELEMENT A. Background Information As is the case in most of California, the Eden Area is subject to risks from seismic activity. The Eden Area is located in the San Andreas Fault Zone, one of the most seismically-active regions in the United States, which has generated numerous moderate to strong earthquakes in northern California and in the San Francisco Bay Area. -
Division 2 Earthwork
Division 2 Earthwork 2-01 Clearing, Grubbing, and Roadside Cleanup 2-01.1 Description The Contractor shall clear, grub, and clean up those areas staked or described in the Special Provisions. This Work includes protecting from harm all trees, bushes, shrubs, or other objects selected to remain. “Clearing” means removing and disposing of all unwanted material from the surface, such as trees, brush, down timber, or other natural material. “Grubbing” means removing and disposing of all unwanted vegetative matter from underground, such as sod, stumps, roots, buried logs, or other debris. “Roadside cleanup”, whether inside or outside the staked area, means Work done to give the roadside an attractive, finished appearance. “Debris” means all unusable natural material produced by clearing, grubbing, or roadside cleanup. 2-01.2 Disposal of Usable Material and Debris The Contractor shall meet all requirements of state, county, and municipal regulations regarding health, safety, and public welfare in the disposal of all usable material and debris. The Contractor shall dispose of all debris by one or more of the disposal methods described below. 2-01.2(1) Disposal Method No. 1 – Open Burning The open burning of residue resulting from land clearing is restricted by Chapter 173-425 of the Washington Administrative Code (WAC). No commercial open burning shall be conducted without authorization from the Washington State Department of Ecology or the appropriate local air pollution control authority. All burning operations shall be strictly in accordance with these authorizations. 2-01.2(2) Disposal Method No. 2 – Waste Site Debris shall be hauled to a waste site obtained and provided by the Contractor in accordance with Section 2-03.3(7)C. -
Bray 2011 Pseudostatic Slope Stability Procedure Paper
Paper No. Theme Lecture 1 PSEUDOSTATIC SLOPE STABILITY PROCEDURE Jonathan D. BRAY 1 and Thaleia TRAVASAROU2 ABSTRACT Pseudostatic slope stability procedures can be employed in a straightforward manner, and thus, their use in engineering practice is appealing. The magnitude of the seismic coefficient that is applied to the potential sliding mass to represent the destabilizing effect of the earthquake shaking is a critical component of the procedure. It is often selected based on precedence, regulatory design guidance, and engineering judgment. However, the selection of the design value of the seismic coefficient employed in pseudostatic slope stability analysis should be based on the seismic hazard and the amount of seismic displacement that constitutes satisfactory performance for the project. The seismic coefficient should have a rational basis that depends on the seismic hazard and the allowable amount of calculated seismically induced permanent displacement. The recommended pseudostatic slope stability procedure requires that the engineer develops the project-specific allowable level of seismic displacement. The site- dependent seismic demand is characterized by the 5% damped elastic design spectral acceleration at the degraded period of the potential sliding mass as well as other key parameters. The level of uncertainty in the estimates of the seismic demand and displacement can be handled through the use of different percentile estimates of these values. Thus, the engineer can properly incorporate the amount of seismic displacement judged to be allowable and the seismic hazard at the site in the selection of the seismic coefficient. Keywords: Dam; Earthquake; Permanent Displacements; Reliability; Seismic Slope Stability INTRODUCTION Pseudostatic slope stability procedures are often used in engineering practice to evaluate the seismic performance of earth structures and natural slopes. -
Management of Slope Stability in Saint Lucia
Issue #12 December 2012 Destruction of a house caused by a rainfall-triggered landslide in an urban community - Castries, Saint Lucia. Management of Slope Stability in highlights Communities (MoSSaiC) in Saint Lucia The Challenge: affected by heavy rains and hurricanes. Even “everyday” Reducing Landslide Risk low magnitude rainfall events can trigger devastating landslides. For the city’s inhabitants, this has meant In many developing countries, landslide risk is frequent loss of property and livelihoods, and even increasing as unauthorized housing is built on already loss of lives. As with any disaster risk, this also means landslide prone hillslopes surrounding urban areas. that the island is constantly under threat of reversing This risk accumulation is driven by growing population, whatever economic progress and improvements to increasing urbanization, and poor and unplanned livelihoods it has made. Yet, by taking a community- housing settlements, which result in increased slope based approach to landslide risk management, Saint instability for the most vulnerable populations. In Lucia has shown that even extreme rainfall events, addition, the combination of steep topography of such as Hurricane Tomas in October 2010, can be volcanic islands in the Eastern Caribbean and the weathered by urban hillside communities. climate patterns of heavy rains and frequent cyclonic Saint Lucia’s success in addressing landslide haz- activity, are also natural conditions contributing to the ards in urban communities is a result of the innova- high -
Coastal and Other Hazards (Se)
Goleta General Plan /Coastal Land Use Plan 5.0 Safety Element CHAPTER 5.0 SAFETY ELEMENT: COASTAL AND OTHER HAZARDS (SE) 5.1 INTRODUCTION General Plan Law Requirements [GP] The Safety Element is one of seven general Safety Element Policies plan elements mandated by state law. The SE 1: Safety in General scope of the Safety Element is specified in SE 2: Bluff Erosion and Retreat Section 65302 (g) of the California SE 3: Beach Erosion and Shoreline Hazards SE 4: Seismic and Seismically Induced Hazards Government Code as follows: SE 5: Soil and Slope Stability Hazards SE 6: Flood Hazards The general plan shall include a safety SE 7: Urban and Wildland Fire Hazards element for the protection of the SE 8: Oil and Gas Industry Hazards community from any unreasonable SE 9: Airport-Related Hazards. SE 10: Hazardous Materials and Facilities risks associated with the effects of SE 11: Emergency Preparedness seismically induced surface rupture, ground shaking, ground failure, tsunami, seiche, and dam failure; slope instability leading to mudslides and landslides; subsidence and other geologic hazards known to the legislative body; flooding; and wild land and urban fires. The safety element shall include mapping of known seismic and other geologic hazards. It shall also address evacuation routes, peak-load water supply requirements, and minimum road widths and clearances around structures, as those items relate to identified fire and geologic hazards. Coastal hazards such as bluff retreat and shoreline erosion are also addressed in this element, as are hazards associated with oil and gas production, processing, and transport. California Coastal Act Requirements [CP] The California Coastal Act (Coastal Act) requires new development to be sited and designed to minimize risks, ensure stability and structural integrity, and neither create nor contribute significantly to erosion or require the construction of new shoreline protective devices that would substantially alter natural landforms along coastal bluffs and cliffs. -
Green Terramesh Rock Fall Protection Bund
Double Twist Mesh Project: 112 Bridle Path Road Date: May 2016 Client: Private Residence, Heathcote Valley Designer: Engeo Consulting Ltd Contractor: Higgins Contractors Location: Christchurch Green Terramesh Rock Fall Protection Bund The 22 February 2010 Christchurch earthquake triggered numerous rock falls causing damage to homes built close to cliffs. Many of those that survived were red zoned by the Government due of the risk of further rock fall or cliff collapse. The area around Heathcote Valley and in particular Bridle Path road was identified as an area of high risk requiring some form of rock fall protection structure to be constructed in order to protect dwellings from rock fall in the event of any further earthquakes. Geofabrics offers a range of solutions that includes certified catch fences and Green Terramesh rockfall embankments. A rockfall embankment was the preferred solution for this site which has the potential to experience multiple rock fall events. The use of Green Site Preparation Terramesh allows the embankment slopes to be steepened and the footprint reduced to form a stable and robust bund having high energy absorption characteristics. The structure is typically filled with compacted granular material or engineered soil fill with horizontal soil reinforcement (geogrid or DT mesh) inclusions. The front face can either be vegetated or finished with a rock veneer. Rockfall embankments have undergone extensive full scale testing in Europe. Actual rock impacts in excess of 5000kJ into Green Terramesh rockfall embankments located in Northern Italy have been back-analysed and the design methodology verified using numerical modelling (FEM) techniques. This research has resulted in the development of design charts to provide designers with a Bund Design simplified design method based on rock penetration depth. -
Seismic Hazards Mapping Act Fact Sheet
Department of Conservation California Geological Survey Seismic Hazards Mapping Act Fact Sheet The Seismic Hazards Mapping Act (SHMA) of 1990 (Public Resources Code, Chapter 7.8, Section 2690-2699.6) directs the Department of Conservation, California Geological Survey to identify and map areas prone to earthquake hazards of liquefaction, earthquake-induced landslides and amplified ground shaking. The purpose of the SHMA is to reduce the threat to public safety and to minimize the loss of life and property by identifying and mitigating these seismic hazards. The SHMA was passed by the legislature following the 1989 Loma Prieta earthquake. Staff geologists in the Seismic Hazard Mapping Program (Program) gather existing geological, geophysical and geotechnical data from numerous sources to compile the Seismic Hazard Zone Maps. They integrate and interpret these data regionally in order to evaluate the severity of the seismic hazards and designate Zones of Required Investigation for areas prone to liquefaction and earthquake–induced landslides. Cities and counties are then required to use the Seismic Hazard Zone Maps in their land use planning and building permit processes. The SHMA requires site-specific geotechnical investigations be conducted identifying the seismic hazard and formulating mitigation measures prior to permitting most developments designed for human occupancy within the Zones of Required Investigation. The Seismic Hazard Zone Maps identify where a site investigation is required and the site investigation determines whether structural design or modification of the project site is necessary to ensure safer development. A copy of each approved geotechnical report including the mitigation measures is required to be submitted to the Program within 30 days of approval of the report. -
Prediction of the Dynamic Soil-Pile Interaction Under Coupled Vibration Using Artificial Neural Network Approach
Geo-Frontiers 2011 Advances in Geotechnical Engineering Geotechnical Special Publication No. 211 Dallas, Texas, USA 13-16 March 2011 Volume 1 of 6 Editors: Jie Han Daniel A. Alzamora ISBN: 978-1-61782-594-1 Printed from e-media with permission by: Curran Associates, Inc. 57 Morehouse Lane Red Hook, NY 12571 Some format issues inherent in the e-media version may also appear in this print version. Copyright© (2011) by the American Society of Civil Engineers All rights reserved. Printed by Curran Associates, Inc. (2011) For permission requests, please contact the American Society of Civil Engineers at the address below. American Society of Civil Engineers 1801 Alexander Bell Drive Reston, VA 20191 Phone: (800) 548-2723 Fax: (703) 295-6333 www.asce.org Additional copies of this publication are available from: Curran Associates, Inc. 57 Morehouse Lane Red Hook, NY 12571 USA Phone: 845-758-0400 Fax: 845-758-2634 Email: [email protected] Web: www.proceedings.com TABLE OF CONTENTS VOLUME 1 FOUNDATIONS AND GROUND IMPROVEMENT DEEP FOUNDATIONS I Prediction of the Dynamic Soil-Pile Interaction under Coupled Vibration Using Artificial Neural Network Approach .............................................................................................................................................................................................................1 Sarat Kumar Das, B. Manna, D. K. Baidya Predicting Pile Setup (Freeze): A New Approach Considering Soil Aging and Pore Pressure Dissipation...........................................11