Chapter 11 -- Safety Chapter 11--Safety
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Chapter 11 -- Safety Chapter 11--Safety 11.1 Introduction.................................................................................................................................11-1 11.1.1 Scope of the Safety Element..........................................................................................11-1 11.1.2 City of Merced Emergency Response/Disaster Plan .....................................................11-1 11.2 Relevant Issues............................................................................................................................11-2 11.2.1 Seismically Induced Ground Shaking............................................................................11-2 11.2.2 Ground Failure...............................................................................................................11-5 11.2.3 Dam Failure/Seiche........................................................................................................11-8 11.2.4 Flooding.......................................................................................................................11-10 11.2.5 Urban Fires & Wildland Fires......................................................................................11-16 11.2.6 Airport Safety Zones....................................................................................................11-24 11.2.7 Crime & Policing .........................................................................................................11-27 11.2.8 Hazardous Materials & Waste .....................................................................................11-29 11.3 Safety Goals, Policies, and Actions ..........................................................................................11-30 11.4 Technical Data..........................................................................................................................11-39 11.4.1 Definitions...................................................................................................................11-39 11.4.2 Dam Failure Characteristics.........................................................................................11-40 11.4.3 Hazards Unknown in the Merced Planning Area.........................................................11-40 11-0 Chapter 11 Safety 11.1 INTRODUCTION issues as well as hazard response. Section 11.2 includes the goals, policies, and The main purpose of the Safety Element is implementing actions. Section 11.4 contains to provide policies and implementing technical information and support data of actions aimed at reducing injuries, death, the hazards analysis. The Safety Element is property damage, and the economic and one of the seven required elements of the social dislocation resulting from natural General Plan per State law. hazards. The Safety Element is based on an analysis of geologic and other hazards 11.1.2 City of Merced Emergency relevant to Merced and on ways of Response/Disaster Plan protecting the community from any unreasonable risk associated with such In 2003, the City of Merced updated its hazards. Emergency Response/Disaster Plan and a countywide plan was also adopted. Both 11.1.1 Scope of the Safety Element plans are updated as needed to respond to new hazards. The Plan addresses The Safety Element provides a systematic mitigation, planning, response, and recovery approach for responding to hazards relevant activities for various emergency situations. to the City of Merced through a set of goals, The Plan consists of: 1) general policies, and actions designed to deal with information; 2) initial response operations; those hazards. This report recognizes that 3) extended operations; and 4) recovery. hazards are an unavoidable aspect of society and that, therefore, some degree of risk is The purpose of the plan is to provide inherent in everyday life. emergency planning, organization, and response. The Plan deals with emergency The proposed Merced growth boundary (or management through the Incident Command SUDP/SOI) has no known history of, or System (ICS)/National Incident known geographical conditions for, surface Management System (NIMS), law rupture, tsunamis, or hydro-compaction. All enforcement, traffic control, fire, medical, other hazards relevant to Merced, however, rescue and radiological material, shelter, and are addressed in more detail in other support and resources. The plan is designed sections of this Element. This introduction to prepare the community for responding to includes an overview of the City’s an emergency situation in a highly Emergency Response/Disaster Plan. Section 11.2 presents an analysis of the relevant 11-1 Merced Vision 2030 General Plan Chapter 11--Safety organized and efficient way so that chaotic The amount of damage to structures from an situations are avoided. earthquake is determined by several factors: (1) Distance from the earthquake epicenter; 11.2 RELEVANT ISSUES (2) nature of the ground; (3) type of construction; and (4) the duration of the Seismically induced ground shaking, ground shaking. failure, dam failure/seiche, flooding, urban and wildland fires, airport safety, crime and policing, and hazardous materials are considered the relevant hazards to the City of Merced. 11.2.1 Seismically Induced Ground Shaking Seismic safety has traditionally been looked at as an individual/family responsibility; however, because we are spending increasing amounts of time in public areas and because of our increased reliance on public services, our personal safety in an The Distance From the Epicenter earthquake may depend in large part on Merced is vulnerable to shaking from a what our City, employer, or local merchant number of faults that run through the has done to prepare. Earthquake activity mountains to our east and west. These have can include severe ground settling, dam shaken Merced in the past. Of most failure, and landslides, but most people notoriety is the San Andreas Fault, 58 miles equate earthquakes with the movement of away. There are, however, four active faults the earth along a fault or fracture zone. closer to Merced than the San Andreas. Merced is vulnerable to possible earthquake These faults are shown in Figure 11.1. damage from earthquake epicenters in other portions of the State, earthquakes on The Nature of The Ground “nearby” faults, and earthquakes on what are Earthquake shockwaves are “carried” by the now undiscovered faults within the Central relatively loose, wet soils that exist between Valley. Los Banos and Merced. For this reason, Merced is somewhat more likely to Historically, Merced has received several jolts a experience heavy shaking from surrounding year from earthquakes in surrounding parts parts of the state as will some of its of the State. Typically, it has been the larger neighbors. Areas of Merced with high water earthquakes from these areas that cause tables and loose soils are likely to damage. Because earthquakes run in experience damage because of the “cycles of frequency and intensity” where a shockwave carrying ability of the ground. period of long inactivity is followed by Next to damage from ground shaking, several medium and large quakes it is liquefaction is the most serious earthquake theorized that Merced, along with the rest of hazard. California, may experience rising earthquake risks 11-2 Merced Vision 2030 General Plan Chapter 11--Safety GEOLOGIC FAULTS IN AND AROUND Figure MERCED COUNTY 11.1 11-3 Merced Vision 2030 General Plan Chapter 11--Safety The Type of Construction Used Hazard Response -- Ground Shaking Typically, buildings designed and When ground shaking occurs, people are constructed since the mid-1970’s and generally encouraged to stay where they are according to modern codes, have generally and to prepare themselves for any performed very well during earthquakes. aftershocks that may take place. For these However, the following construction types reasons, the discussion in this chapter will have garnered some concern within the not involve evacuation routes and minimum seismologist community regarding their road widths as they pertain to evacuation. safety in earthquakes: a. Concrete-Frame Structures Built Before Merced currently has 21wells throughout the 1976 City. Eight of these wells pump directly into the water main system, and 10 of these Although Merced has relatively few wells pump into the City’s four water buildings of this type, the cost of towers. It is Merced’s current policy to strengthening the necessary connections place one well in each square mile of the is a relatively inexpensive procedure, City, reinforce each of the well stations while potential benefit is great. These beyond required seismic standards, supply buildings generally house industrial each well with standby power to last about activities and their collapse could cause three normal-use days, interloop the water severe economic loss and possibly the main system, and construct water piping of release of hazardous materials. flexible ductile iron. For these reasons, it is b. Un-reinforced Masonry Buildings reasonable to expect newer parts of the City to retain much of its water supply capacity Although Merced has relatively few in the event of an earthquake. buildings of un-reinforced masonry, it will be necessary to reinforce these structures as modifications are proposed. If structures of this type are identified as unsafe or a potential risk to the general public, repairs/upgrades could be required. It has been determined that an earthquake of 5.0 magnitude or greater