Chapter 2 Reading Summary

Chapter 2 Reading Summary - Chapter 2: Measuring...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 2: Measuring Earthquakes History: The First Ways of Recording Earthquakes (before 1800s) - First phase, they started to define earthquakes by Intensity: They measured earthquakes during this time by simply looking at the intensity of the earthquake o Pignataro 1783 devised a basic intensity scale in Italy o Revided by Even in 1828 with a 6 phase scale: This was used in the Netherlands Earthquake in 1828 - Second phases, Define areas of equal intensity o Noggerath in 1847 with the Rhenish earthquake, he defined the quake by 2 areas of intensityw ith lines known and isoseismals o Malaga, Spain in 1680: they could roughly estimate source, fault and locations with just intensity reports. What is intensity: The intensity is determined by distance/depth of the source, the material and the topography of the site experiencing ground movement. - Wave Attenuation: There is a decrease in wave amplitude and ground intensity as the wave moves through ground and energy is loss by absorbtion. o Geometrical Spreading: in a wave front, waves ripple like a pond and being to lose amplitude and intensity o Deeper earthquakes cause lower surface intensities than shallower ones of the same size o Groundshaking is the greatest above the source - Rock Type and Amplifying Intensity: Certain weak materials like sand and mud can amplify ground shaking at some frequencies due to poor elastic response o 1989 Loma Prieta Earthquake Southeast of San Francisco. Ground shaking amplified by the foundation
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/19/2011 for the course GEOL 240 taught by Professor Sammis during the Fall '08 term at USC.

Page1 / 4

Chapter 2 Reading Summary - Chapter 2: Measuring...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online