Question

ELASTIC COEFFICIENTS AND SEISMIC VELOCITIES FOR SELECT COMMON ROCKS TABLE 2.1 Vp (m/s) (m/s) Poisson's Ratio Rock Type Density Young's Modulus 2124 1470 1.44 69 0.040 Shale (AZ) 0.120 0.120 2319 1524 1.52 65.7 Siltstone (CO) 2.50 0.156 3633 231957 6384 Limestone (PA) 2.71 Limestone (AZ)2.44 Quartzite (MT) 2.66 Sandstone (WY) 2 2.28 2.67 2.70 2.70 2.64 0.337 0.170 0.636 0.140 0.487 0.544 0.680 0.255 27501718 1.60 62.47% 4965 3274 1.52 65.96% 2488 1702 1.46 68.42% 4336 2860 1.52 65.96% 4680 2921 160 62.41% 0.180 0.060 0.115 0.181 0.200 52903239 1.63 61.24% 0.146 0.270 0.141 Slate (MA) Schist (MA) Schist (CO) Gneiss (MA) Marble (MD) Marble (VT) Granite (MA) Granite (MA) 3189 2053 1.55 64.38% 5587 3136 1.78 3643 23551.55 64.65% 3967 2722 1.46 68.62% 3693 2469 1.50 66.85% 50433203 1.57 63.51% 6569 3682 1.78 56.05% 51243070 1.67 59.91% 4776 2984 1.60 62.47% 2.87 56.13% 2.71 0.343 Gabbro (PA) Diabase (ME) Basalt (OR) Andesite (ID) Tuff (OR) 2.65 3.05 2.96 2.74 2.57 0.354 0.727 1.020 0.630 0.540 0.014 0.096 0.162 0.271 0.220 0.180 996 659 1.51 66.20% (Problem 2.6 from the textbook) In most common rocks density varies from 2.0 to 3.0 g/cm, Young's modulus varies from 0.12 x 1011 to 1.1 x 1011 N/m2, and Poisson's varies from 0.04 to 0.3. Using the Table 2.1 spreadsheet template, determine density variations or velocities. Describe your findings ratio variations in elastic coefficients have the greatest effect on P-wave

Answer 1

1. Take value for shale and slate.

Densities are same but velocity is multifold or many times other velocity.

So we can say Vp depends more on elastic coefficients.

2. Take values for schist(MA) and schist(CO) .

Density same but velocity different for different values of elastic coefficient.

Vp depends more on coefficients.