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Non-construction Vibrations
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The free Construction Vibration Damage Guide (CVDG), of which this is one chapter, deals mostly with ground vibration effects on structures, as caused by construction heavy equipment. There is some considerable discussion of blasting-generated vibrations and their potential damages to structures throughout the CVDG, in both the Homeowners and Professional Editions, as they relate to construction vibration damage issues. An introduction to blasting and the vibrations it produces can be found in the CVDG chapter, Blasting Vibrations. However, there are many other sources of vibration which can interact with homes and buildings. While they are not central to the subject of construction vibration and its effects as described in the CVDG, a brief discussion of some of the most common other vibration sources encountered by some home and building owners follows. The purpose of this discussion is to provide people who are experiencing vibration effects from non-construction sources with some starting points for their own investigation. Non-blasting Quarry and Mine Operations Blasting vibrations from quarries, surface mines and construction are discussed in numerous locations in the CVDG. However, while blasting might be the highest energy vibration source at a mine, it is not the only one. Rock crushers, used to break rocks into more useful sizes after blasting, produce low frequency vibrations that may affect some structures close to the crusher. Transport of rock in heavy vehicles may also produce felt vibrations. Since these sources are much longer in duration than blasting, they may constitute an issue for structures near to those operations. Traffic on streets and highways is often a semi-continuous source of low-level vibration. Depending on the distance of the structure from the road, the type, speed and amount of the traffic, and the condition of the road, vibrations may be felt, particularly from large, heavy trucks (e.g. semi trucks) passing at high speed. It has long been recognized that the semi-continuous nature of traffic vibrations requires lower acceptable peak particle velocities than those acceptable in short duration blasting.[1],[6] Vibrations from traffic of all forms and their effects are probably the most studied and well-understood of vibrations from non-blasting sources. There are literally hundreds of scientific research papers devoted to that topic. Many are available free on the Internet for those with a need to understand traffic vibrations. I have also provided references to several of those studies in the CVDG.
That monitoring was very poorly done. It lacked any "baseline" measurements of weekend or night hours when no construction was occurring. However, some breaks in work during lunch periods and at the end of days after stoppage of construction allowed an estimation of the contribution of traffic to vibration. The construction activities themselves, during the monitored period shown in the seismograph histogram report, included excavation with a large excavator, laying of water main and backfill with the excavator. Looking at the histogram record, shown at left, of one such day's work, the lunch periods and pre- and post-construction-work periods stand out as being strikingly low in vibration, even though these are among the busiest traffic hours on the street. This picture could change if you live very near an interstate or any other highway with large amounts of tractor-trailer (semi-truck) traffic.[6] Because such vehicles both weigh a great
deal and travel at high speed, the potential exists for accumulated vibration to create some damage. Again, the mere fact that you feel some vibration does not imply causation of damage, by itself.
Anyone who has sat in a car at a rural railroad crossing knows that passing trains can produce ground vibration. However, the cases of most concern are those where railways are present in cities or towns, either to move freight or as part of a mass transit system. Many factors come into play in determining whether train traffic can cause damage in buildings, including those associated with the building (age, construction, maintenance), those associated with the site (distance from railway, soil and bedrock properties) and those associated with traffic on the railway (condition of track and bed, age of track and type of rolling stock, speeds, and weight of train cars), among others. Because there are so many factors which relate to damage potential in these situations, it is often difficult to predict which situations will be prone to inducing damage. Again, one of the best sources for information on railway vibration is the High-Speed Ground Transportation Noise and Vibration Impact Assessment (shown at right) of the Federal Department of Transportation. Some cities (e.g. New York City) also set vibration standards for railways. Because railway vibration is semi-continuous, these standards tend to be much lower in peak particle velocity than those set for short duration blasting or even those which currently govern construction vibration (e.g. the highest allowed PPV in New York around railways can be as low as 0.05 in/sec, depending on the surrounding structures). "Fracking" and Oilfield Wastewater Disposal Hydraulic fracturing ("fracking") of oil and natural gas-bearing rock formations is a subject of much current controversy with respect to generation of small earthquakes and, on seemingly rare occasions, mostly relatively minor damage to structures. Fracking involves pumping at high pressure a complicated mixture of water, sand, surfactants ("detergents") and other additives into oil or gas-bearing rocks at depth in order to crack the rocks and release the trapped petroleum components for recovery. Any technology capable of breaking rock at depth has at least a potential for causing ground vibrations. There are some documented examples where fracking is thought to have caused small earthquakes and minor home damage. Damage to structures from fracking operations is controversial, but rapidly becoming accepted in the scientific community as at least possible. Oilfield wastewater disposal is often confused with fracking, because it has some similarity with fracking in terms of equipment and its effects. Produced water from oil wells is often too saline to be disposed of by discharge into natural streams. One form of oilfield wastewater disposal involves pumping the water at high pressure into rock formations, cracking them as a result. One state in the U.S. in particular, Oklahoma, has experienced an increase in earthquakes, some damaging to buildings, which correlates with increased oilfield and shale gas production activities there - mostly wastewater disposal. Several scientific studies have indicated a link between increased seismicity (earthquakes) in Oklahoma and oil production activities there.[3],[4] Other U.S. states, e.g. New Mexico and Colorado,[8] have experienced increases in seismicity attributed to wastewater disposal activities, but its real impact on structures remains controversial in some quarters. Predictably, those in the oil industry, much like those in the construction industry with respect to construction damage, argue that fracking does not damage homes. There are other concerns regarding fracking and wastewater disposal in oil and shale gas fields, including the potential for ground water contamination and ground water use in generally arid areas in the U.S. West. These concerns cannot be ruled out completely, though they seem less well-supported than the seismic issues identified in Oklahoma and elsewhere. For a good layman's introduction to fracking and other oilfield-related issues, there is a helpful series of National Geographic articles available online.[3],[4],[7] Machine tools with rotating or reciprocating parts, like lathes, turbines, stampers, forgers and many other types also produce vibrations, the intensity and frequency distribution of which depend on the tool, its weight, its operating speed and whether it is rotary or impact in nature. Since vibration in rotating devices wastes energy and may reduce their precision, there is a whole field devoted to measuring and reducing machine tool vibration. If you live very near a steel mill, foundry or other large manufacturing facility, machine tool vibration may be detectable on your property. Its transmission through the ground can be measured on the property using the same instrumentation used for construction vibration. Damage has been reported from such operations in the past, as well as several times to Vibrationdamage.com. Ground Impacts The CVDG has considerable discussion of the vibration potential of ground impacts of many sorts. Just driving, as well as using, tracked vehicles (excavators, dozers, etc.) near homes can produce vibrations which not only exceed construction vibration standards, but whose broad frequency distributions are virtually certain to result in resonant enhancement of the home vibration, all as discussed in the CVDG's Vibration Potential chapter. However, ground impacts can occur from a number of other sources, such as dumping of large rocks, tree felling, and development procedures, for example. If your home is within 50 feet or so of such large ground impacts, the potential for at least some damage is real. Since ground impacts have many sources, any operations involving such impacts should be vibration monitored. Other Sources of Vibration
There are, of course, many sources of non-construction ground vibration, beyond those mentioned here. Many of these produce near-continuous vibration with relatively low velocities (intensities). When evaluating the potential for damage from such a near-continuous source, the duration and frequency distribution of the vibration components are at least as important as the vibration velocity (PPV). Because homes respond differently to different frequencies, especially those near the home resonance frequencies, even small vibrations near those resonances can be dangerous to a home, if they persist long enough. Vibrations which have a broad spread of frequencies, particularly ones generated by impact or impact-like activities (e.g. driving of tracked equipment over distances), are virtually certain to lead to amplification of the vibrations in homes. Thus, an understanding of the true frequency distribution, best gotten from FFT analysis of the vibration waveform, is critical to estimating damage potential. If you are having issues which you attribute to vibration, the first step is to establish that vibration is present and determine its velocity. Vibration monitoring firms or some acoustic monitoring firms located in most large cities can do this for you, or you can use a smart phone or tablet computer to do it yourself. See the CVDG's Vibration Monitoring chapter for more information on how to carry out your own monitoring.
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Traffic vibrations are often used by
contractors as rationalizations for damage done by road construction projects (see Counterarguments in the CVDG Pro for more on this). One 6-month road construction job involved work on two moderately busy city streets having both car and
large truck (no tractor-trailer rigs) traffic. After initial extensive damage was done by the contractor pounding on pavement with an excavator,
vibration monitoring was started. 
In all cases, where even heavy truck traffic (e.g. full large trash pickup trucks as at right, note
blue seismograph box on the opposite side of the street just behind truck at left of photo) went as close as two feet from the seismograph head, no vibrations above 
Homes can experience occasional vibrations from many sources in addition to the ones discussed here and elsewhere in the CVDG. Sonic booms, activities of people
in the home (e.g. exercise equipment like that at right), buried water and gas lines, and even some home mechanical systems can all be sources of vibrations. However, most of these are simply too localized, too small in energy, or of too short duration to be much of a factor in causing significant home-wide damage in the overwhelming
majority of cases. Therefore, 
