3 Your Taskdesign and construct a seismograph using common household and craft materials provided
4 An excellent design will be… made of the common inexpensive materials provided for this exercise;capable of determining the relative size of each disturbance it measures;capable of measuring vibrations continuously for at least one minute;capable of capturing the time when these disturbances occurred;capable of measuring vibrations from three different sources: a bang on or shaking of the table holding the seismograph; a person jumping up and down on the floor next to the table on which your seismograph is located; and a ball bounced off of a wall or floor nearby.
5 Seismograph – records ground motion as a continuous function of time. Seismoscopes - indicate that motion has occurred, azimuth, perhaps some simple measure of size.Seismograph – records ground motion as a continuous function of time.
6 First Seismoscope AD 132, Zhang Heng of China's Han dynasty 2 meters in diameterEight points around the top were dragon's heads holding bronze ballsPendulum insideOn at least one occasion, probably at the time of a large earthquake in Gansu in AD 143, the seismoscope indicated an earthquake even though one was not felt. The available text says that inside the vessel was a central column that could move along eight tracks; this is thought to refer to a pendulum, though it is not known exactly how this was linked to a mechanism that would open only one dragon's mouth. The first ever earthquake recorded by this seismograph was supposedly somewhere in the east. Days later, a rider from the east reported this earthquake.
7 European Seismoscopes (function) Proposed by J. de la Haute Feuille - bowl of mercury.1731 – Nicholas Cirillo - simple pendulumsDomemico Salsano, a clock-maker and mechanic of Naples, invented a "geo-sismometro”common pendulum, eight and a half "parisian" feet long.equipped with a brush to record motion with slow-drying ink on an ivory slab.In 1703, J. de la Haute Feuille proposed filling a bowl to the brim with mercury, so that an earthquake would cause some of the mercury to spill out (de la Haute Feuille, 1703; Favaro, 1884). In order to determine the direction of the shock, the mercury spilling out in each of the eight principal directions of the compass was to be collected in cavities or other containers.The honor of being the first European to record the use of a mechanical device as an aid to the study of earthquakes goes to Nicholas Cirillo (1747). Cirillo employed simple pendulums in an investigation of a series of earthquakes in Naples in He observed the amplitude of pendulum oscillations at the locations where the shaking was most severe, and also at locations somewhat removed from the zone of severest shaking. He found the amplitude to decrease with the inverse square of the distance, a result he anticipated from "the common laws in other sorts of motions" (Cirillo, 1747, p. 682).
8 Seismoscope (time)A. Cavalli bowl of mercury with moving pots beneath to “catch” every minute (timing never built)Duca della TorrePendulumA record, written by a pencil attached pressed gently against paper.Hair on the pendulum mass was a hair which would start the clock
9 Seismoscope (period) 1844 – James Ford – Inverted pendulum design Recognized value of long period instrumentcommon pendulum, 10-20ft = period of 4-5s
10 Seismograph 1875 – Cecchi (Italy) – seismoscope start a clock start into motion the recording surface at the time of an earthquake.
11 Seismograph 1889- von Rebeur's horizontal pendulum Much of the next phase of the development (to the present) was focused on using electronics to both extend the dynamic range of the instrument while also minaturizing them.
21 Three Sumatra Earthquakes Magnitude 9.0December 26, 2004Magnitude 8.7March 28, 2005Magnitude 6.8April 10, 2005Seismograms are shown on the same scale.AS1 SeismogramsSame Distance,Different MagnitudesThree Sumatra EarthquakesRecorded atWeston ObservatoryBoston College∆=133°Seismograms are shown on the same scale.
22 Parkfield, CA Earthquake Same Earthquake, Different DistancesSeismograms are shown on the same scale.Phoenix Country Day School, Paradise Valley, AZ∆=7°AS1 SeismogramsWeston High School,Weston, MA∆=38°Parkfield, CA EarthquakeMagnitude 6.0, 09/28/04Time (sec/102)
23 Same Magnitude, Different Distances Seismograms are shown on the same scale.El SalvadorMagnitude 7.7, January 13, 2001∆=33°IndiaMagnitude 7.7, January 26, 2001∆=106°AS1 SeismogramsEl Salvador and India EarthquakesRecorded at Devlin Hall Boston College
24 The Great Sumatra Earthquake of 2004 Seismograms Recorded at Boston CollegeMagnitude 9.0December 26, 2004Magnitude 8.7March 28, 2005