Abstract: An earth-tremor-responsive light contained in a main housing is described having a back member for mounting against a vertical wall and a light transmitting front cover; a stand-by battery; a light emitter; electrical circuit elements connecting the battery to the light emitter through an inertial switch which is actuated by acceleration resulting from earth tremors, the inertial switch including a switch chamber having a generally horizontal shallow upwardly-facing conical surface with a central apex at a lower point thereof; a spherical ball urged by gravity to rest in a central disposition on the conical surface; a vertical shaft projecting externally of the main housing and disposed in the chamber aligned with the central apex and above the ball, the shaft being guided for vertical movement in the chamber and having a lower end resting on top of the ball; a spring urging the shaft downwardly to a set position against the ball at rest in its central disposition, whereby a peak acceleration resulting from a

Abstract: In a longwall mining operation, a panel to be extracted is formed in a seam of mine material by longitudinally extending headgate and tailgate entries with the panel beginning in a set-up room and ending at a termination line in a recovery room. The recovery room is developed in two stages and is supported by primary and secondary roof support systems that include mechanical roof bolt assemblies, roof trusses, and channel members. The effectiveness of the roof support systems to support the overlying rock strata and withstand the abutment pressure exerted on the strata by the advancing longwall face as it approaches the recovery room is monitored by an instrumentation plan. Data gathered from the instruments is continually monitored as the longwall panel recovery operation progresses.

Abstract: An earthquake sensor includes a base support, a first element pivotably supported onto the base support at a first pivot location, a second element pivotably supported onto the first element at a second pivot location and sensor apparatus operative to sense earthquake actuated vibration of the second element and to provide an output indication thereof.

Abstract: A detector system and method for accurately indicating over- and under pressurization conditions within the piping network owned by the end user, includes the steps of: (a) introducing the natural gas stream to a filter selected from a group that includes at least activated charcoal and impingement adsorbing and absorbing media whereby natural gas contaminants concentrated in the gas stream at sufficient levels to be a detection threat by aperiodic loading of such network in which contaminants become clumped into packets due to dampening effects of the compressor-driven equipment and multiple customer outlet usage that add to aperiodic loading of the natural gas stream coupled with surprising longevity of the in situ contaminant, is filtered from the gas stream and captured, (b) passing filtered sample of natural gas and a sample of ambient air to a pair of identical systems excepting the set point level of each is formulated to indicated the occurrence of either an over-pressurization condition or of an unde

Abstract: An improved system for shutting off utilities, such as gas and electricity, automatically in the case of an emergency, such as an earthquake, fire and the presence of hazardous fumes. The device includes a box containing the main control unit mounted on the gas main outside the building. The box includes a motion detector which triggers a relay which cuts the power to the gas valve causing the flow of gas to be cut off during an earthquake. An electrical signal is supplied by a smoke detector or a hazardous fumes detector to the relay to trigger the relay and the relay interrupts the power to the gas valve shutting the flow of gas to the building. The relay provides an electrical signal to a power breaker and a water valve in order to shut off electrical and water supply to the building. After the emergency passes and the utilities are checked for damages the system can be reset manually. Power to the box is provided by running a powerline to it.

Abstract: An inference device for discriminating an earthquake includes an ON/OFF signal generating means for generating an ON/OFF signal corresponding to an oscillatory wave, a characteristic parameter extracting means for extracting at least one of three characteristic parameters consisting of an ON period, an ON time sum total and a maximum ON time value based on the generated ON/OFF signal, and an inference means for inferring for each ON period based on the extracted characteristic parameter whether or not an earthquake happens.

Abstract: An earthquake detector motion sensitive device capable of detecting any one or more of the conditions of angular tilt, vibration or acceleration having an electrically conductive pendulum with a main mass located next to its suspension point and having an extension arm that extends below the main mass. When the pendulum suspension point is acted upon by an outside force of vertical or lateral motion, the extension arms lower end will travel farther than the distance that the main mass travels, causing the lower end of the pendulum extension arm to mechanically amplify the movement of the main mass. At the lower end of the extension arm is an upper switch contact which is suspended into the opening of a lower switch contact. During seismic activity the two switch contacts will be caused to touch each other which will activate an audio signaling device and charge an electrolytic capacitor.

Abstract: A seismic switching device that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period.

Abstract: The Earthquake Motion Detector Alarm consists of a pendulum hanging within a sensor ring. At the instant of earth movement, the pendulum weight will make contact with the sensor ring setting off an audio alarm and floodlamp. The magnetized sensor ring can be adjusted so the detector can be installed to function on all vertical walls by positioning the pendulum weight within the ring.

Abstract: A vibration sensor has a bell shaped casing with a recess formed at its closed end. The recess has a flat bottom and slanted side walls so that an opening of the recess is larger than the bottom of the recess. The casing serves as a first electrode. Mercury of drop-shape is disposed in the recess, and at least two second electrodes are disposed circumferentially around the mercury. This structure creates three vibration systems; i.e., the mercury vibrates in three different modes. The first vibration system is based on the surface tension of the mercury. A portion of the mercury protruding from the recess undergoes vibration. The second vibration system is due to gravity acting on the mercury. The mercury rolls out of the recess between the electrodes in response to vibrations. The third vibration system is based on resonance. The mercury resonates between the electrodes.

Abstract: A method and apparatus for detecting the seismic signal generated by a tornado and providing timely warning of the tornado's approach. The invention involves the use of a geophone or velocity transducer (3) to detect the seismic surface waves generated by the tornado. The output of the geophone passes to the microchip (4) installed with the alarm system (5) within the building (6). Within the microchip the signal passes through the A/D converter (7), to the band-pass filter (8), and then to the signal-to-noise comparator (9). When the signal-to-noise ratio exceeds a specified level, the switch (10) is closed and the alarm (5) is activated.

Abstract: An earthquake sensor in which a weight falls from a support surface and activates a switch in the event of an earthquake. The support surface is preferably a bell with its opened end downward and the weight resting on a concave, recessed region at the closed end of the bell. The bell is preferably supported by a shaft along the axis of the bell, the tip of which the bell pivots about like a pendulum. A conductive cylinder encircles the bell near its bottom. When the earth moves, the weight falls down the inclined surface of the bell, wedging between the bell and the cylinder, forcing the bell to pivot over to electrically connect the bell to the cylinder. In an alternative embodiment, the weight electrically connects the bell and the cylinder, and the bell does not pivot.

Abstract: An earthquake warning device including a speaker disposed in a housing, a casing disposed above the housing, a pair of electrically conductive sheet members disposed in a lower portion of the casing and electrically coupled to the speaker, a support disposed in the casing having a flat upper surface, and an electrically conductive ball disposed on the flat upper surface of the support. The ball will move away from the flat upper surface and downward to electrically connect the sheet members together when a vibration occurs to cause the speaker to generate a warning sound.

Abstract: A rockbolt monitor monitors increased loadings on a rockbolt in underground mines. The monitor includes a rockbolt plate fitted on the rockbolt to engage the surface of the rock, a stack of belleville washers on the end of the rockbolt outside the rockbolt plate and a spring seat plate outside the belleville washers. When a nut is fitted onto the rockbolt and torqued, the belleville washers will compress to provide the desired force urging the rockbolt plate against the surface of the rock. This spring arrangement allows relative movement of the rockbolt plate on the rockbolt in response to ground movement, such as caused by blasting. The load indicator itself includes a threaded sleeve screwed into a threaded bore in the spring seat plate. A spring loaded piston rides in the sleeve. It is biased into engagement with the rockbolt plate.

Abstract: A landslide detecting apparatus which is laid under the ground include: a light source; a lens device for converting a beam of light from the light source into a parallel pencil of rays; a condensing lens device; a light detecting device; and a shading mechanism adapted to partly or entirely intercept the pencil of rays in response to external pressures applied thereto. Any change in the earth's crust in a direction to cause a landslide causes the shading mechanism to operate in correspondence with the magnitude of the change so as to partly intercept the parallel pencil of rays and cause a change in the quantity of light detected, making it possible to obtain a quantitative knowledge of the change in the earth's crust.

Abstract: The present invention is a moisture stabilization control system used to prevent structural damage to foundations resulting from forces exerted by the expansion and contraction of underlying soil. Stress sensors are employed to monitor the stress applied against the foudnation. When abnormal amounts of stress are sensed by the system, it compensates for the decreased support of the foundation by injecting water into the soil supporting that foundation until the level of stress is equalized and at the proper amount. The present invention is designed such that it can provide water to the soil in specified zones, thereby relieving localized depletions and preventing substantial structural damage to any foundation.

Abstract: An earthquake detector is provided for mounting on a structural member of a building or the like, which is resistant to false alarms arising from door slamming, traffic, running, sonic booms, etc., and yet which is sensitive to earthquakes and especially to P-waves which often precede destructive S-waves. The apparatus includes a motion detector for generating an alarm signal, which is responsive only to vibrations below a frequency of about 14 Hz, to avoid false alarms from non-earthquake vibrations. The detector can include a cantilevered beam device with a weight on its free end, and which generates a signal as the weight moves up and down, and a filtering circuit that passes primarily signal components of a frequency between 3 and 14 Hz. The beam device preferably is highly damped so its response is only slightly higher at its resonance frequency than at other frequencies.

Abstract: An earthquake detector is provided, which can sound an alarm several seconds before the arrival of the major shock of an earthquake, and which can be easily adjusted for sensitivity. For detecting local earth shaking of at least a predetermined dangerous acceleration level that constitutes a significant danger, a detector is provided that responds to shaking motion of an acceleration level between one-half and one-eighth the predetermined dangerous acceleration level to detect P-waves that arrive before the destructive S-waves, and which generates an audible alarm upon such detection. In one detector, two mercury-type switches are mounted with their directions of sensitivity both horizontal but perpendicular, the switches being mounted on a circuit board that can be tilted to alter their sensitivities.

Abstract: A combined earthquake sensor and night light having a base with a bottom portion resting on a support surface subject to vibrations. A top portion of the base is provided with a reflective surface and a centrally mounted lamp. A transparent cylinder is mounted on the base member to suspend a multifaceted spherical crystal above the light source by means of an elastic helical spring to enable the spherical crystal to move in all directions. Vibrations generated by an earthquake are transmitted to the base member causing movement of the crystal giving a visual indication of the vibrations by light reflection and diffractio. In the static mode the unit serves as a decorative lamp.

Abstract: A motion and orientation responsive device having a pendulum pivotally mounted between its ends, and means for detecting relative displacement of the upper pendulum end and a zero position reference on the pendulum support from certain normal relative positions thereof in response to either or both translational and rotational displacements of the device. Presently preferred embodiments of the invention are a seismic or earthquake alarm, an intrusion alarm, and a tilt alarm. In these preferred embodiments, the pendulum shaft is a slender resilient wire, and its pivot is situated close to its lower center of mass in order to amplify the lateral motion of the upper pendulum end for a given angle of pendulum rotation and thereby enhance the sensitivity of the device to low magnitude displacements.

Abstract: A data logger having a plurality of input ports has a library of predefined selectable input data conversion protocols. Inputs are individually controllable as to the type of sensor conversion. The data logging rate is varied during the recording period to ensure that all meaningful data values are recorded, while at the same time ensuring that the entire data storage capacity of the data logger will be substantially fully utilized at the completion of the recording period. Sensitivity is constantly adjusted to ensure that no meaningful data values are missed, whether the pertinent information concerns high frequency, low amplitude fluctuations (e.g., noise), or concerns longer-term trends, ignoring short-term variations.

Abstract: The present invention relates to a system for acquisition and separation of the effects of simultaneous sources of electromagnetic field. According to the invention the system comprises an array of n pick-ups (1a . . . 1e) connected to registration means (2), the minimum number n of pick-ups per array being equal to 2s+2, where s is equal to a number of simultaneous sources to be analysed.

Abstract: An illuminating device comprises a housing having a light compartment and an off push-button located on the front wall thereof. The housing encloses a battery powered electrical circuit including a normally-open motion detection switch, a light bulb, a latching circuit, a control gate, and a normally open, momentary-closing reset switch. The housing is adapted to be removably fastened at a convenient location on an internal wall of a home. When the wall is shaken by a major earthquake that is likely to knock out the electric service in the area involved, the initial closing of the motion detection switch latches the latching circuit to provide a high level signal that opens the control gate and completes the electrical circuit to ground, thereby turning on the light bulb. When the earthquake occurs during the night time, the housing can be removed from the wall and used as a portable flashlight.

Abstract: A seismic detector which generates an electrical signal in response to the occurrence of a vertical seismic wave predetermined magnitude is mounted in a weather-proof container in or adjacent an inhibitable building. A circuit breaker to interupt electrical power to the building is mounted in the same container and connected to open in response to signals from the detector. Gas and water line connections each with a solenoid operated shut-off valve are separately housed in a weather-proof container in or adjacent the building and the valves are connected so that they will close in response to a signal from the seismic detector. The entire system is rendered fail safe through the use of an interruptible power supply system housed in the container with the seismic detector and connected to energize the gas and water line cut off valves to hold them in open condition.

Abstract: Apparatus for shutting off utilities, such as gas and electricity, automatically in the case of an emergency, such as an earthquake. The utility can be a gas or electric line and, at shutdown, an alarm may be sounded and a light activated. The apparatus includes a box mounted adjacent the main power panel. The box includes a solenoid wired to the main breaker switch of the main power panel and a start/stop switch coupled to the solenoid valve at the main gas line. If an earthquake hits, the solenoid to the electric panel is activated to shut off the main switch. This in turn activates the solenoid to the gas line which turns off the gas. Simultaneously, a signal alarm coupled to the box sounds and a light also coupled to the box is lit. The alarm may be turned off manually and the light kept on, if desired. After the emergency, the control panel may be reset and the gas turned on after manually opening the gas valve and re-lighting the pilot.

Abstract: An alarm assembly specifically designed to warn sleeping occupants within a dwelling structure as to the occurrence of earth tremors such as those caused by relatively serious earthquakes wherein an activating member is movably positioned relative to a supporting base and is sensitive to such earth tremors to the extent of being displaced within a predetermined range of movement and into activating engagement with a switching assembly also mounted on said base to cause operation and/or activation of preferably an audio alarm to awaken the sleeping occupants.

Abstract: Earthquake sensing device which has a ball with a metallic surface which is resting atop a perch having a narrow upper base. In case of a tremor, the ball falls off the perch and is intercepted by a contact plate and thereby closes an electric circuit which includes the ball, the perch, the contact plate, a power supply and an electric sounder, which is activated to sound an alarm.

Abstract: A motion detector for detecting earthquakes or the like provides a warning signal when vibrations having a frequency of the order of the natural frequency of an earthquake tremor are detected. A preferred embodiment of the device employs a vertical spring barb member which is mounted on a suitable support on one end thereof. A coupler member is supported on the other end of the barb member. This coupler member is connected through a coil spring to an inertial mass which is vertically positioned generally in external concentricity with the barb and the coupler, the spring being either compressed or extended to provide a resilient coupling between the coupler member and the inertial mass. The spring and mass elements are chosen so as to have a natural resonant frequency at the frequency of an earthquake tremor (0.7-3 Hz), or other disturbance to be detected.

Abstract: This invention relates to an integrated acoustic network system to provide warning of impending groundfall in underground mines. The system includes a plurality of geophones which derive acoustic signals by which the source of seismic disturbances is located, and an array of high frequency piezoelectric sensors which pick up signals from small ground disturbances which precede groundfall. A warning system is provided both at the scene of mining operations and at a central location of impending groundfall and of the location of its occurrence.

Abstract: The ambient broadband radio frequency field strength from broadcast stations is monitored (FIG. 4) by periodic sampling (50, 52). A warning indication is provided if the field strength drops significantly. Drops in such field strength have been correlated empirically with the occurrence of seismic activity, usually several days later. Thus the indication serves as an early warning of an impending earthquake. In one preferred embodiment, a broadband, horizontal, very long monopole antenna (40) was connected to a rectifying and smoothing circuit (FIG. 3) to provide a dc output proportional to the ambient rf field. This voltage is digitized (50), and using a suitably-programmed computer (52), the digital version of the field strength signal is sampled once per minute (78). A cumulative or running average of the minute samples is calculated (80) and held. Once per hour the latest running average is stored (84) and a standard deviation (SD) of the last 24 hourly stored running averages is calculated (88).

Abstract: A digital recorder and method for digitizing and recording seismic events, the recorder being capable of lengthy stand-by periods during which it records lesser events of little interest in a static buffer and then displaces these events with more recent events when the static buffer is full. The recorder is self powered and controlled by a microprocessor to transfer strong-motion signals representing important seismic events from the static buffer into a static memory which is kept alive by suitable back-up batteries and comprises a cartridge separable and retrievable from the recorder after a major seismic event. The information in the recorder also is accessible through a serial port for reading out to a central data processor. The seismic information is specially compressed and formatted to increase the amount of data recorded by eliminating data that is essentially redundant.

Abstract: A seismic actuation system incorporating a plurality of motion sensors. The motion sensors included a housing in which a weight is supported for slidable movement along a single direction within the housing. The sensors are mounted to a horizontally disposed enclosure. The sensors are arranged so that the directions of travel of the weights within the enclosures are uniformly arranged so that vibration of sufficient magnitude in the horizontal plane will cause one or more of the weights to move. By adjusting the mass of the weights, the sensitivity of the sensors can be adjusted. When a seismic event of sufficient magnitude occurs, the weight becomes displaced from a central position within its housing and moves to one or the other end of the housing to activate the contacts. Activating the contacts completes a circuit so that one or more warnings, such as bells, lights, or spoken words, are produced or one or more safety devices are actuated.

Abstract: A novelty for apparently indicating earthquakes, including a circular base marked with concentric circles on its upper side defining different earthquake intensities, a frame upon the base supporting a freely depending electrical contact through a supported circular contact so that in case the device is tilted, the contacts touch and thus close a circuit to a warning alarm.

Abstract: A device for alerting miners of an unsafe condition existing in mine shafts includes a surface-engaging member, a chamber-defining member having a compressible medium therein, and a plunger connected between the surface-engaging member and chamber-defining member. The plunger is slidably engaged with the chamber at one end in contact with the compressible medium therein so that the plunger moves in response to a compression force applied to the surface engaging member and applies pressure on the compressible medium. A switch for actuating an alarm in response to a predetermined amount of movement between the surface-engaging member and the chamber-defining member, is provided and a visual indicator operatively associated with the compressible medium is utilized so as to set the switch to establish the predetermined amount of movement necessary to actuate the alarm.

Abstract: A seismic alarm system incorporating a plurality of motion sensors. The motion sensors included a housing in which a weight is supported for slidable movement along a single direction within the housing. The sensors are mounted to a horizontally disposed enclosure. The sensors are arranged so that the directions of travel of the weights within the enclosures are uniformly arranged so that vibration of sufficient magnitude in the horizontal plane will cause one or more of the weights to move. By adjusting the mass of the weights, the sensitivity of the sensors can be adjusted. When a seismic event of sufficient magnitude occurs, the weight becomes displaced from a central position within its housing and moves to one or the other end of the housing to activate the contacts. Activating the contacts completes a circuit so that one or more warnings, such as bells, lights, or spoken words, are produced.

Abstract: A thin wire with known properties of thermal expansion is suspended under constant tension between two fixed points and passes through an aperture in a measuring plate mounted on a wall or ceiling. The plate is mounted to permit relative movement of the plate with respect to the wire so that the plate aperture can be initially centered with respect to the wire. A pair of cursors are movably mounted on the plate relative to the aperture and have intersecting or overlapping cursor elements which cooperate with linear measurement scales on the plate to enable the operator to establish coordinates for the cursor element intersection point as an aid in placing the plate aperture at a location where the wire is at the center of the aperture. At periodic intervals the cursors are realigned with the wire to determine the wire's coordinates and whether the plate aperture has moved from its initial location relative to the stationary wire.

Abstract: A small-sized, high sensitivity seismograph comprising a first seismometer for detecting left-right ground motions, a second seismometer for detecting up-down ground motions, two sets of protective device for preventing the seismographic detectors from damage due to excessive motions, an alarm system, and an adjustable device for adjusting the sensitivity of the alarm system. All of the above-described devices are provided in a case.

Abstract: A device for signalling seismic movements or the like, comprising a first pair of electric contacts, one of said contacts being vibratile relatively to a horizontal rest position and the other contact of said pair being adjustably spaceable from said rest position; a second pair of electric contacts, one of the contacts being vibratile relatively to a generally vertical rest position and the other contact of said pair being adjustably spaceable from said rest position; an electric circuit connected to said two pairs of contacts and being closed when the vibratile contact of at least one of said pairs contacts its corresponding adjustable contact, at least one warning unit being inserted into said circuit to emit warning signals when said circuit is being closed.

Abstract: This invention relates to an apparatus and method for detecting and measuring the position of a fracture in solid formations, such as for example a grout filled borehole. An electrical element is placed the length of the borehole prior to filling the hole with grout. When the hole is filled and the grout solidified, any fracture in the grout also breaks the electrical element. The element is constructed such that its electrical capacitance is a known function of its length. The element is constructed of easily frangible materials so that it is severed in close proximity to the grout fracture. The capacitance of the element after the fracture can be measured using suitable instrumentation. The position of the break is a function of the capacitance as measured after the break.

Abstract: An alarm system is provided for detecting a seismic tremor and for generating an audio and/or visual alarm signal which varies depending upon the magnitude of the seismic tremor. In the preferred form of the invention, the alarm system comprises a free running oscillator having a pair of terminals the capacitive value across which controls the frequency of the oscillator. A fixed oscillator plate is electrically connected to one terminal while a variable position oscillator plate is electrically connected to the other terminal and has an inertial mass secured to it. A spring positioned between the plates urges the variable position capacitor plate away from the fixed plate but still enables the variable position capacitor plate to move in response to a seismic tremor thus varying the capacitive value between the terminals and the frequency of the oscillator. The output from the oscillator is coupled through a phase locked loop circuit which tracks the oscillator output.

Abstract: An earthquake alarm system detects lateral impulse movements of a building or other structure and generates an audible sound as a result of the lateral detector moving beyond a preset limit. The lateral detector comprises a solid inertial mass that detects the lateral movement of the support as the measure of an impending earthquake. Electrical contacts associated with the mass and the support energize an audible circuit for generating an alarm to the occupants of the structure.

Abstract: A ferrite core is suspended from the base of a borehole in a tunnel roof structure and is positioned within coil turns located at the roof surface such that movement of the roof structure causes displacement of the core with respect to the coil turns thus producing a change in inductance. The coil and core are incorporated as a frequency-determining element in an LR oscillator. Therefore, movement of the tunnel roof structure is reflected as a change in the frequency of the oscillator. This frequency is monitored and, if the change exceeds a predetermined threshold, an alarm is given. Several methods of suspending the core in the coil are disclosed, one of which allows for a non-verticle borehole.

Abstract: The present alarm has a pendulum-operated switch apparatus including a pair of closely spaced, flexible, steel strips extending down from an insulation housing. These strips carry closely spaced, confronting switch contacts below the housing. One of these strips carries a pendulum weight at its lower end. To adjust the sensitivity of the switch, the other strip is adjustable toward the weighted strip by a metering pin operated by an adjusting screw through a gear reduction. Conductive rods extend into the housing to provide electrical connections to the upper ends of the strips. Each rod has a non-circular enlargement engaging the outer face of the corresponding strip and an inner end which is deformed laterally outward against the inner face of the strip.

Abstract: An inverted, compound pendulum, which may be set in motion by a seismic variance, activates a photoelectric switching system. Logic circuitry in electrical contact with the switching system discriminates in a pre-determined manner with respect to the repetition rate of signals transmitted by the switching system and selectively activates and controls an alarm. Circuitry in the device permits display of the device's status and interacts with a self-contained power source to permit continued operation despite interruption of external power.

Abstract: Movement of the roof of a mine shaft is detected by unlatching of a position sensing device in an elevated position causing it to drop to a lowered position pivotally suspended by a link from a bracket yieldably held in abutment with the roof ceiling. The bracket is positioned on the lower end of an elongated support bolt by a nut acting as a latch releasing member engageable with a latch element connected to the link for latched support of the sensing device in the elevated position.

Abstract: A device to monitor movement of a surface such as, for example, the roof of a mine tunnel or the like and to provide an indication if that movement exceeds some predetermined creep rate or velocity. The device includes a sensing member formed of a material whose precise creep characteristics as a function of stress and strain are known. The device includes a sensing member formed of a material whose precise creep characteristics as a function of stress and strain are known.

Abstract: A device for giving a visual or audible indication of motion such as impact, vibration or the like, which has a contact element supported on a base. When motion occurs, due to earthquake or other causes, a contact element is displaced completing an electrical circuit. In a preferred embodiment, the contact element comprises an elongate pin which topples in response to motion. In another embodiment the contact element may be a spherical element. The device may also be used as an intrusion alarm having an auxiliary member co-operable with the device so that the device can be attached to a door or a window as a trip alarm.