DOCSLIB.ORG

Design Strategies for Metal Wall and Roof Systems

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Design Strategies for Metal Wall and Roof Systems | THE BUILDING ENVELOPE | By Russell M. Sanders, AIA, and Craig A. Hargrove, AIA, LEED AP, Hoffmann Architects DESIGN HOFFMANN ARCHITECTS STRATEGIES FOR METAL WALL AND ROOF SYSTEMS Russell M. Sanders, AIA, is President of Hoffmann Architects, an archi- LEARNING OBJECTIVES tecture and engineering firm specializing in building exteriors. In addition After reading this article, you should be able to: to building enclosure evaluation for existing structures, he specializes in design detail assessment and constructability review for new construc- + DESCRIBE the materials and finishes typical of metal wall and roof tion. He can be reached at: [email protected]. assemblies, including the benefits and shortcomings of each, and the Craig A. Hargrove, AIA, LEED AP, Senior Vice President and Director of applications to which they are best suited. Architecture with Hoffmann Architects, oversees demanding high-perfor- mance building envelope projects. Manager of the firm’s New York office, + DISTINGUISH between “open” and “closed” metal wall systems, defining he leads project teams in developing design details that meet weather each in terms of its waterproofing strategy, as well as its compatibility integrity, energy efficiency, and aesthetic goals with cost-effective solu- tions. He can be reached at: [email protected]. with exposed or concealed fastener designs. + CONTRAST “hydrokinetic” and “hydrostatic” metal roof assemblies and ears ago, prefabricated metal panel wall and explain the relationship between these water protection approaches and roof systems did not find wide acceptance architectural or structural metal roof systems. in high-end commercial applications. While + EXPLAIN how best to address design considerations, such as expansion, these systems were cost-effective, aesthetic differential movement, structural integrity, weather protection, thermal perceptions relegated them to large storage performance, and condensation, for typical metal wall and roof assemblies. buildings, manufacturing facilities, and big box stores. However, versatility, reliable per- formance, and relatively low installed-costs have now made these systems attractive in Sponsored by more sophisticated applications. Today, owners and Yarchitects often collaborate to use these products in distinctive and aesthetically innovative design 42 | BUILDING DESIGN+CONSTRUCTION | January/February 2021 | BUILDING ENVELOPE | HOFFMANN ARCHITECTS solutions. Manufacturers, recognizing sion. This can also occur in areas that see an opportunity, have expanded their significant amounts of water accumulation, product lines with the aim of amplifying OF HOFFMANN ARCHITECTS PHOTOS COURTESY such as gutters. When using zinc panels, product use across a range of building protective coatings applied to the at-risk types. Of course, no building enclosure surfaces should be considered. system is without design challenges Copper is an extremely durable mate- and considerations. rial option that generally does not require From structural and weatherproofing a protective coating. Although, as with to energy efficiency, the longevity and zinc, the use of such coatings at the un- performance of metal wall and roof sys- derside of panels can be advisable under tems depends on an understanding of certain conditions. Uncoated copper also material properties, code requirements, tends to stain adjacent surfaces and and best practices. materials over time. Stainless steel never requires a protec- MATERIALS AND FINISHES tive coating and provides a bright appear- Most metal wall and roof systems are ance. An aesthetic alternative is terne proprietary, each manufacturer having plate, stainless steel coated with an alloy their own profiles, method of attach- that is over 99% tin. Terne plate provides a ment, and performance specifications. weathered appearance similar to zinc but, However, there are basic similarities in like zinc, requires ventilation behind the these assemblies. panels to prevent pitting and corrosion. Metal systems come in a variety Depending on the material used, any of materials, with aluminum being number of finishes and coatings may be the most common due to its relative selected based on aesthetic and perfor- durability, corrosion resistance, and mance requirements. Paints, such as light weight. Aluminum panels are fluoropolymers, enjoy wide use in metal available in flat plates—solid plate wall applications, as they come in a range approximately one-eighth inch thick—or of colors, and are resistant to fading. composite panels, where foam insula- Porcelain enamel coatings fuse tion is sandwiched between two layers powdered glass to the metal surface at of thin sheet aluminum. a high temperature. Like fluoropolymers, Steel is another commonly used ma- they are durable and offer designers a terial. Strong and providing superior im- number of appearance options. pact resistance, steel is often selected Many finishes have been developed for façades in high-traffic areas and for more for their protective properties than roofs that must span longer distances for their appearance options. Galvaniz- between supports. However, steel’s ing, for instance, is a sacrificial protec- strength means it is heavier than other tive coating of zinc applied to steel that materials, necessitating more underly- has a silver-gray appearance and is used ing structure to support the load. Steel to prevent corrosion of the underlying also requires a protective coating to steel. Anodizing, an electrolytic process prevent deterioration due to corrosion. used on aluminum to increase its cor- Zinc panels are also becoming more rosion resistance, is only available in a popular because of the distinctive ap- limited range of colors (typically black, pearance and durability afforded by the bronze, and silver). surface patina acquired during weather- It’s important to remember that not all ing. Patina formation occurs naturally in finishes are compatible with all materi- the presence of moisture and carbon di- als. Even when an appropriate coating or oxide. Care should be taken where mois- paint is selected, application timing can ture may be present without sufficient significantly impact longevity. Typically, it carbon dioxide, such as at the underside Common problems in metal panel systems include: is best to apply coatings and paints after 1) condensation, 2) corrosion, 3) movement and of roof panels, where condensation and water intrusion, 4) peeling coatings, and the metal has been formed, to avoid other incidental moisture can cause corro- 5) discoloration and staining. hairline breaks in the material at bends. 44 | BUILDING DESIGN+CONSTRUCTION | January/February 2021 HOFFMANN ARCHITECTS PREFABRICATED METAL WALL SYSTEMS This securement can be achieved in two ways: by With metal panel systems Generally speaking, there are two types of metal use of “exposed” or “concealed” fasteners. offering an expanded range wall systems available: “closed” and “open.” With exposed fastener systems, panels are of features and options, examples of metal-clad Closed assemblies (also called “barrier” or “face- attached to the substrate using fasteners that are structures can be found in sealed” systems) use the metal wall panels to re- screwed through the panel and left exposed for nearly all building types, sist the infiltration of weather (air and water) into the ease of installation and aesthetic effect. While the including this luxury apartment tower. building. The metal wall panel system is the air and fasteners are often gasketed to limit water infiltra- moisture barrier of the façade. To achieve weather tion, this method is most commonly employed in protection, the joints between the metal panels open panel systems. must be sealed to form a comprehensive barrier. Systems using concealed fasteners employ Open systems, as the name implies, do not clips to secure panel ends to the sub-framing sys- provide the primary protection against air and mois- tem with bolts. This method can provide a clean, ture infiltration. In these applications, a second- uninterrupted look to the metal panel system in ary means of protection must be included behind either closed or open assemblies. the panels, with consideration given to the way in which moisture that permeates the cladding can PREFABRICATED METAL ROOF SYSTEMS be directed back to the exterior. Rainscreens are Prefabricated metal roof systems are broadly de- a common form of open system that have become fined as being either “hydrokinetic” or “hydrostatic.” increasingly popular in the last decade. Hydrokinetic systems are not necessarily “wa- How metal wall panel systems are installed and ter-tight.” These assemblies shed water by moving attached to the substrate (and ultimately to the it across their surface and off the roof as quickly building structure) is another defining element of as possible. This requires that hydrokinetic roofs their design. The panels are most commonly se- have adequate pitch to effectively move water and cured to a metal sub-framing system consisting of limit infiltration beneath panels. Since panel joints “z” girts, metal studs, or proprietary configurations. are not weathertight, hydrokinetic systems require BDCuniversity.com | BUILDING DESIGN+CONSTRUCTION | 45 | BUILDING ENVELOPE | using sealant or solder for additional weather integrity. DESIGN CONSIDERATIONS HOFFMANN ARCHITECTS Whether designing a prefabricated metal wall system, roof system, or both, the architect or engineer must address certain fundamental design
Load more

Recommended publications
  • Physical Environment Lake Koshkonong EA
    Chapter 3, Affected Environment – Physical Environment Lake Koshkonong EA Physical Environment Lake Koshkonong lies within the Southeast Glacial Plains Ecological Landscape. The Southeast Glacial Plains Ecological Landscape makes up the bulk of the non-coastal land area in southeast Wisconsin. This Ecological Landscape is made up of glacial till plains and moraines. Most of this Ecological Landscape is composed of glacial materials deposited during the Wisconsin Ice Age, but the southwest portion consists of older, pre-Wisconsin till with a more dissected topography. Soils are lime-rich tills overlain in most areas by a silt-loam loess cap. Agricultural and residential interests throughout the landscape have significantly altered the historical vegetation. Erosion Lake Koshkonong was born with an irregular shoreline. The lake has been seeking a natural shoreline of rock, gravel or sand. Such names as Black Banks, and exposed, eroded peat bank typifies the problem. Threinen (1952) identified the problem over 50 years ago and stated, “Further evidence can found from the sight of uprooted trees and from duck hunters who will exclaim that what was their duck blink has now been claimed by the lake”. Due to the combined effects of ever-increasing water levels and the loss of aquatic plants, erosion of the wetlands and some adjacent uplands continues to date. Lake Koshkonong ranks 12th in the number of erosion Table 1. Number of Erosion Control Permits by lake issued in the South Central control permits issued in the DNR Region. Lakes with 20 permits or less are not shown. Data are taken from South Central Region (Table 1).
    [Show full text]
  • Climate Change in Selawik, Alaska Strategies for Community Health
    Climate Change in Selawik, Alaska Strategies for Community Health ANTHC Center for Climate and Health Funded by Report prepared by: Michael Brubaker, MS Prithviraj Chavan, P.E. James Berner, MD Mike Black John Warren, P.E. ANTHC recognizes all of our technical advisors for this report. Thank you for your support. LeeAnn Ayres, Selawik National Wildlife Reserve Eric Hanssen, ANTHC Tanya Ballot, Native Village of Selawik Millie Hawley, Maniilaq Association James Beylund, City of Selawik Lucy Snyder, Native Village of Selawik Susan Clark, Native Village of Selawik Allison Woodward, University of Alaska Fairbanks Paul Eaton, Maniilaq Association © Alaska Native Tribal Health Consortium (ANTHC), May 2012. Through adaptation, negative health effects can be prevented. TABLE OF CONTENTS Summary 1 Introduction 7 Community 9 Climate 11 Land 15 River 17 Water 19 Waste Water 21 Solid Waste 23 Transportation 25 Housing 27 Energy 29 Food 31 Conclusion 33 Figures 1. Map of Maniilaq Service Area 8 2. Google Maps view of Selawik and region 10 3. Mean Monthly Temperature Selawik (SNAP) 12 4. Mean Monthly Precipitation Selawik (SNAP) 13 5. Circulating Water, Vacuum Sewer Systems 29 6. Climate Change Health Assessment Findings, Selawik Alaska 34 Appendices A. Selawik Participants 35 B. Selawik Climate and Health Web Resources 36 C. General Climate Change Adaptation Guidelines 37 References 38 Cover Art: Whale Bone Mask by Larry Adams Rural Arctic communities are vulnerable to climate change and residents seek adaptive strategies that will protect public health. In the Inupiat community of Selawik, climate change is impacting the weather, land, river, wildlife, plants, and the lives of the people who live there.
    [Show full text]
  • Historic Stone Highway Culverts in New Hampshire Asset Management Manual
    Historic Stone Highway Culverts in New Hampshire Asset Management Manual Prepared for: New Hampshire Department of Transportation, Bureau of Environment, Concord. Prepared by: Historic Documentation Company, Inc., Portsmouth, RI September 2009 TABLE OF CONTENTS 1.0 INTRODUCTION .........................................................................................................1 1.1 Purpose......................................................................................................................1 1.2 Why Preserve Historic Stone Culverts .....................................................................2 2.0 IDENTIFYING HISTORIC STONE CULVERTS.......................................................4 2.1 General Information .................................................................................................4 2.2 New Hampshire Stone Culverts................................................................................7 2.3 Stone Box Culverts ...................................................................................................8 2.4 Stone Arch Culverts................................................................................................14 3.0 MAINTAINING HISTORIC STONE CULVERTS ..................................................16 3.1 General Maintenance Discussion ...........................................................................16 3.2 Inspection & Maintenance Program ......................................................................17 3.3 Clear Waterway .....................................................................................................18
    [Show full text]
  • Arctic and Subarctic Construction - Buildings
    UFC 3-130-07 16 JANUARY 2004 UNIFIED FACILITIES CRITERIA (UFC) DESIGN: ARCTIC AND SUBARCTIC CONSTRUCTION - BUILDINGS INACTIVE APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED UFC 3-130-07 16 JANUARY 2004 UNIFIED FACILITIES CRITERIA (UFC) DESIGN: ARCTIC AND SUBARCTIC CONSTRUCTION - BUILDINGS Any copyrighted material included in this UFC is identified at its point of use. Use of the copyrighted material apart from this UFC must have the permission of the copyright holder. U.S. ARMY CORPS OF ENGINEERS (Preparing Activity) NAVAL FACILITIES ENGINEERING COMMAND AIR FORCE CIVIL ENGINEER SUPPORT AGENCY Record of Changes (changes are indicated by \1\ ... /1/) Change No. Date Location INACTIVE _____________ This UFC supersedes TM 5-852-9, dated 25 March 1988. The format of this UFC does not conform to UFC 1-300-01; however, the format will be adjusted to conform at the next revision. The body of this UFC is the previous TM 5-852-9, dated 25 March 1988. UFC 3-130-07 16 JANUARY 2004 FOREWORD The Unified Facilities Criteria (UFC) system is prescribed by MIL-STD 3007 and provides planning, design, construction, sustainment, restoration, and modernization criteria, and applies to the Military Departments, the Defense Agencies, and the DoD Field Activities in accordance with USD(AT&L) Memorandum dated 29 May 2002. UFC will be used for all DoD projects and work for other customers where appropriate. UFC are living documents and will be periodically reviewed, updated, and made available to users as part of the Services’ responsibility for providing technical criteria for military construction. Headquarters, U.S. Army Corps of Engineers (HQUSACE), Naval Facilities Engineering Command (NAVFAC), and Air Force Civil Engineer Support Agency (AFCESA) are responsible for administration of the UFC system.
    [Show full text]
  • Route Weather Resilience and Climate Change Adaptation Plans Scotland
    Route Weather Resilience and Climate Change Adaptation Plans Scotland Scotland Route: WRCCA plan Contents Director Route Asset Management statement 2 Executive summary 3 Introduction 4 Scotland Route WRCCA strategy 7 Scotland Route vulnerability assessment 8 Scotland Route impact assessment 19 Scotland Route WRCCA actions 35 Management and review 39 Purpose of this document This document sets out a Weather Resilience and Climate Change Adaptation (WRCCA) plan for Scotland Route supported by an evaluation of the resilience of rail infrastructure to historical weather events and an awareness of potential impacts from regional climate change projections. The resilience of rolling stock operating within the Route is not specifically assessed. The approach taken is consistent across all Network Rail’s Routes, and describes our current planned mitigations, how we intend to develop the plans further, and how we are improving the embedment of WRCCA across the business to deliver a railway fit for the future. Network Rail 1 Scotland Route: WRCCA plan Director Route Asset Management statement Climate change presents us with an unprecedented challenge to understand how shifts in temperature and rainfall will impact our network and to identify the actions we can take to proactively increase our weather resilience. In response to this challenge Scotland Route has developed a Weather Resilience and Climate Change Adaptation (WRCCA) plan which incorporates a number of programmes and initiatives designed to increase resilience of the railway in Scotland to effects of weather and climate change. Scotland is no stranger to the best and worst of the weather. In recent years we experienced the prolonged spell of heavy snow fall in 2010/11 and the severe rain and wind in 2012 and 2013.
    [Show full text]
  • Numerical Analysis of Ice Loads on Taraldsvikfossen Dam
    th 25 IAHR International Symposium on Ice Trondheim, 23 - 25 November 2020 Numerical analysis of ice loads on Taraldsvikfossen dam Andreas Seger1, 2, Bjørnar Sand1, Bård Arntsen1, Chris Petrich1, Megan O’Sadnick1,2 1 SINTEF Narvik, Narvik, Norway 2 UiT-The Arctic University of Norway, Tromsø, Norway [email protected], [email protected], [email protected], [email protected],[email protected], Static ice loads (ice actions) are a key design parameter for dams in cold climates. Since 2012, ice stresses have been measured at Taraldsvikfossen reservoir located in Narvik, Norway. Similar to earlier observations in Canada, it became evident from the first three years of data that various effects resulted in stresses, including thermal expansion and water level fluctuations, and that the relative dominance of the processes varied between seasons. A numerical model, using the commercially available finite element software LS-DYNA, is presented for the prediction of the stress field in an ice sheet due to temperature changes and water fluctuations as a function of time, under a variety of conditions. The finite element model accounts for variable temperature and properties through the thickness, an elastic foundation representation of the underlying water, nonlinear constitutive behavior of the ice, temperature dependent mechanical properties, flexibility of resisting structures. For verification of the numerical model, results from simulation are compared with measured temperatures and stresses at Taraldsvikfossen reservoir. 1. Introduction The age of the dams in Norway is increasing. The dams are a considerable value in terms of fixed capital assets and future profits. The consequences of a dam failure can often be very significant, causing both environmental and economic damage and loss of life.
    [Show full text]
  • Environmental Impact Assessment of the Citronen Zinc Project, North
    Citronen Base Metal Project Environmental Impact Assessment (Volume 1) January 2015 Rev 6 Licence 2007/02 Licensee Bedford (No. 3) limited (a wholly owned subsidiary of Ironbark Zinc Limited) Prepared by Ironbark Zinc Limited Level 1 350 Hay Street Subiaco 6008 Western Australia Tel.: + 61 8 6461 6350 and Orbicon A/S Ringstedvej 20 DK-4000 Roskilde Denmark Tel: + 45 46 30 03 10 REV. NO ISSUE DATE DESCRIPTION OF REVISION 01 Feb 2011 Draft report issued to BMP. Inclusion of NERI preliminary comments (February 2011). 02 March 2011 Shipping impacts update. Dust impacts update. 03 Aug 2012 Inclusion of BMP comments (April 2011). 04 March 2013 Inclusion of BMP comments (December 2012). Inclusion of BMP comments (February 2013). 05 July 2014 Final report submitted to MLSA (English, Danish, Greenlandic) Inclusion of BMP comments (December 2014). 06 January 2015 Final report submitted to MLSA (English, Danish, Greenlandic) ii Contents 1 EXECUTIVE SUMMARY .................................................................................................. 1 2 INTRODUCTION.......................................................................................................... 11 2.1 Project setting ....................................................................................................... 11 2.2 Ironbark Zinc Limited ............................................................................................ 13 2.3 Project history ....................................................................................................... 14
    [Show full text]
  • Weathertalk for January 2, 1998 Topic
    WeatherTalk for January 2, 1998 Topic: Preliminary Climate Summary for December 1997 The most striking characteristic of December was mild temperatures. Most northern Minnesota counties experienced one of the warmest five Decembers this century and the warmest since 1923 for some communities. Central and southern counties recorded one of the warmest ten Decembers this century. For some communities it was the warmest since 1965, while for others it was the warmest since December of 1959. MSP airport did not record a single day with below normal temperatures until the last day of the month. Precipitation was less than normal for most Minnesota communities, with snow cover well below normal. Total snowfall for the month ranged from 3 to 8 inches, again well below normal. Topic: A Brief History of Snow Shoveling Bernard Mergen in his recent book, Snow in America recounts the history of the snow shovel. As early as 1870, a patent was granted to William Wentworth of Seneca Falls, NY for a snow shovel with a riveted metal tip for scrapping. In 1889 a Lydia Fairweather applied for a patent on a snow shovel that had both attachable scrapper and scooper. The snow scooper, sometimes called a yooper scooper, is a large bucket shaped shovel with sides. It is a common snow removal device in the Upper Peninsula of Michigan and in Maine, where 100 to 200 inches of snow occurs most winters. The first plastic snow shovel patent was granted to a Robert Smith of New Jersey in 1939. These are by far the most popular sold today, many with metal tips for scrapping.
    [Show full text]
  • Dalton Highway
    A Guide's Guide to the DALTON HIGHWAY Northern Alaska Tour Company Written and researched by Robert R. Weeden * Edited by LJ Evans * with special contributions from LJ Evans Jack Reakoff Sarah Manriquez-Trujillo Reference Encyclopedia This section is intended to be an easy and trustworthy source of information for guides needing quick answers to questions that arise during the course of their Dalton Highway adventures. Some entries may seem only distantly apropos to the Dalton Highway/Arctic Alaska theme; however visitor curiosity tends to reflect not only their immediate surroundings but also their prior experiences in the state — as well as any preconceptions they might have brought with them. The overall scope of the project is, for this reason, quite broad. In fact, the previous file became so unwieldy I decided to split the guide into two sections. The first contains information on the human history and culture of Alaska’s Arctic; the second on its natural history. Some entries are duplicated, but only when they contain information important to understanding both human and natural histories – and the specific information in each is different. Thus, this volume contains information of human interactions with snow, and the second an entry detailing the mechanics and bedforms of snow. Both the human and natural landscapes of Alaska’s Arctic are constantly changing, probably now more than ever. This document will, therefore, need constant updating and refreshing. Guides should feel free to make suggestions, point out inadequacies and pass along any additional information. All such contributions will be gratefully received; hopefully, we can together maintain the Guide’s Guide as an important and useful tool for many generations of Dalton Highway guides.
    [Show full text]
  • Chapter 9, Environmental Consequences - Cultural Lake Koshkonong EA
    Chapter 9, Environmental Consequences - Cultural Lake Koshkonong EA Environmental Consequences Physical Erosion Due to the combined effects of ever-increasing water levels and the loss of aquatic plants, erosion of the wetlands and some adjacent uplands has been a problem for at least the last 50 years. RKLD and other citizens have recognized this problem and have attempted to deal with this by “armoring” part of the shoreline. The majority of these projects have included riprap armor (Figures 43 and 44) of wetland shoreland areas that have been eroded and lost over time. Figure 43. 6/13/03; USGS Gage - 776.31 msl; top of riprap protection at Carcajou Shallow Marsh at outside Figure 44. Carcajou Shallow Marsh Date: 5/13/2003 Water corner of riprap lakeward from opening behind Carcajou Elevation: 777.30 msl. Shallow Marsh. Elevation near top of rock is 777.48 msl. During 2002 and 2003, the RKLD worked cooperatively with wetland owners to protect approximately 38% or 4.7 miles of the 12.5 miles of wetland shoreline. In 2001 Act 16, the Legislature granted authorization to the District for a Lake Koshkonong Comprehensive Project (Table 2). Act 16 recognized the placement of breakwater structures was another suitable management approach to prevent wetland losses resulting from wind and seasonal flood conditions. RKLD is also currently involved with the U.S. Army Corps of Engineers (ACOE) in an Ecosystem Restoration Program (under Section 206 of the Water Resources Act) to further restore and protect wetlands and near-shore shallow water areas. The ACOE has identified several places in Lake Koshkonong where off shore breakwaters could provide protected habitat for plants and aquatic life.
    [Show full text]
  • SPCO FY09 Annual Report
    SSttaattee PPiippeelliinnee CCoooorrddiinnaattoorr’’ss OOffffiiccee Annual Report Fiscal Year 2009 This page is intentionally blank. Executive Summary The Joint Pipeline Office is an intergovernmental organization dedicated to overseeing the safe and reliable transportation of petroleum and natural gas products to market while promoting the protection of public health and safety and the environment. The State Pipeline Coordinator’s Office is an agency within the Alaska Department of Natural Resources that is co-located in the Joint Pipeline Office. Pipeline right-of-way leases that are issued by the State of Alaska under Alaska Statute 38.35 fall under the jurisdiction of the State Pipeline Coordinator and are administered by the State Pipeline Coordinator’s Office. The fiscal year 2009 State Pipeline Coordinator’s Office Annual Report describes the status of jurisdictional pipeline right-of-way leases. This report integrates information from all State Pipeline Coordinator’s Office activities and summarizes the prior calendar year's construction, operations, and maintenance activities on jurisdictional pipeline rights-of-way. The sections of this report include an overview of each jurisdictional pipeline, a summary of the annual reports submitted by the lessees, and a description of SPCO oversight programs and SPCO activities during the fiscal year 2009. This report does not provide a comprehensive record of all activities that are undertaken as part of the lessee’s pipeline systems management; rather, this report highlights certain information and activities in order to demonstrate the implementation of SPCO lease oversight. The pipeline ROW leases for SPCO jurisdictional pipelines require that the lessees submit annual reports compiled for the previously concluded calendar year.
    [Show full text]
  • Icequakes on Lakes in Alberta, Canada Authors Jeffrey Kavanaugh
    1 1 Title 2 A New Year’s Day Icebreaker: Icequakes on Lakes in Alberta, Canada 3 Authors 4 Jeffrey Kavanaugh1 5 *Ryan Schultz2 6 Laurence Andriashek2 7 Mirko van der Baan1 8 Hadi Ghofrani3 9 Gail Atkinson3 10 Daniel J. Utting2 11 12 1 University of Alberta, Edmonton, Alberta 13 2 Alberta Geological Survey, Edmonton, Alberta 14 3 Western University, London, Ontario 15 *Corresponding Author: [email protected] 16 17 Accepted in the Canadian Journal of Earth Sciences 18 doi: 10.1139/cjes-2018-0196. 19 2 20 Abstract 21 Any process that causes a sudden brittle failure of material has the potential to cause 22 earthquake-like seismic events. Cryoseisms represent an underreported class of seismic event 23 due to their (often) small magnitudes. In this paper, we document the phenomenon of some of 24 the largest magnitude lake-associated icequakes (ML 2.0) yet reported. These events occurred 25 nearly simultaneously (within ~2 hours) on geographically separate lakes in Alberta, Canada 26 starting January 1 2018. We conjecture that these events were caused by the sudden brittle 27 failure of lake ice due to thermal expansion; the effects of the thermal expansion were 28 compounded by the lack of insulating snow cover, high lake water levels, and a rapid onset of 29 atmospheric warming. These factors also contributed to ice-jacking – a repeating process in 30 which thermal contraction produces tensile cracks (leads) in lake ice that are then filled with 31 water that is frozen during the cooling cycle. Thus, any subsequent thermal expansion must be 32 accommodated by new deformation or brittle failure.
    [Show full text]