principles and applications of microearthquake networks

More documents

Recommendations

Info

~ 16 2. Ins trumeri tic t ion Systems I I I I I I I 1 . 41'00' -REDDlYG I _/! 1.- WILLILS A . .A OROVILLE . A A * a - A. ic; &. I SACRAMENTO A .- A Fig. 3. Distribution of seismic stations (solid triangles) in the USGS Central California Microearthquake Network.
2. I . General Coiisiderations 17 The principal advantage in using a centralized recording system is that a common time base can be established for the entire network. Since only one time base is needed, greater effort can be put into maintaining a dependable and precise time standard. The common time base eliminates the need for separate clock corrections for each station. Keeping separate clock corrections has been a principal headache for seismologists, and errors in clock corrections limit the precision in locating earthquakes. Another advantage is that many seismic signals can be recorded on a common film or magnetic tape medium. Mass recording on film makes it easier to identify seismic events and to read records. The labor involved in reading multichannel film records is typically several times less than that for reading single-channel records. Mass recording on magnetic tape makes it possible to use a computer for more sophisticated analysis. Compared with the 1-mmlsec recording speed used by the standard 24-hr drum recorder, greatly improved time resolution is available with centralized film or tape recording systems. For example, time bases ranging from 10 to 100 mdsec are used routinely for multichannel oscillographic playbacks from tape-recorded data. Finally, having seismic signals from the entire network available at one location permits rapid correction of instrumental malfunctions and permits real-time monitoring and analysis of seismic activity within the network. 2.1.2. Station Distribution and Site Location Previous studies (e.g., Bolt, 1960; Lee et ul., 197 I) suggested that if the crustal structure is homogeneous, stations in a seismic network should be evenly distributed by azimuth and distance. In particular, to obtain a reliable epicenter, the maximum azimuthal gap between stations should be less than 180"; to obtain a reliable focal depth, the distance from the epicenter to the nearest station should be less than the focal depth. For example, focal depths of central California earthquakes are typically 5- 10 km. It follows that an average station spacing 5 not greater than 10-20 km is needed. If earthquakes are uniformly distributed over a region of area A, then a network of approximately A/S2 stations (which are evenly distributed over the region) is required. If earthquakes are concentrated along fault zones, then the minimum spacing applies only for stations near the fault zones, and the total number of stations required could be less. Optimal- distribution of stations has been studied by many authors [e.g., Sat0 and Skoko (1963, Peters and Crosson (1972), Kijko (1978), Lilwall and Francis ( 1978), and Uhrhammer (1 980b)l.
Page 1 and 2: PRINCIPLES AND APPLICATIONS OF MICR
Page 3 and 4: PRINCIPLES AND APPLICATIONS OF MICR
Page 5 and 6: Contents FOREWORD PREFACE vii ix 1.
Page 7: Foreword Earthquakes occur over a c
Page 10 and 11: X PI-
Page 13: PRINCIPLES AND APPLICATIONS OF MICR
Page 16 and 17: 2 1 . It1 trodir ctivn of the earth
Page 18 and 19: frequency of occurrence N by (I .2)
Page 20 and 21: 6 1. Introduction the initial P-ons
Page 22 and 23: 8 1. Ititrodiictioti that changes i
Page 24 and 25: 10 1. Introduction Fig. la. Schemat
Page 26 and 27: 12 Fig. b. Map showing seismographi
Page 28 and 29: 14 1. Introduction indicated the la
Page 32 and 33: 18 2. Itistrirmeritation Systems In
Page 34 and 35: 20 2. Ins trumeti ta tim S ys tems
Page 36 and 37: 22 2. Ins tru inen ta t ion Systems
Page 38 and 39: 24 2. Iris trumentrt tion Systems F
Page 40 and 41: 26 2. Itistrutnetztntioti System 5H
Page 42 and 43: 28 2. Instrumentntior? Systems Fig.
Page 44 and 45: 30 2. Instrumentation Systems The o
Page 46 and 47: 32 2. Instrumentation Systems other
Page 48 and 49: 34 2. Instrumentation Systems 1 0 7
Page 50 and 51: a,No ak) ak) ak) TABLE I Seismic Sy
Page 52 and 53: 38 2. Znstrumentution Systems FREQU
Page 54 and 55: 40 2. Instrumentatiori Systems mome
Page 56 and 57: 42 2. Ins tru rneti totion Sys tenz
Page 58 and 59: 44 2. Instrumentation Systems magne
Page 60 and 61: 3. Data Processing Procedures Micro
Page 62 and 63: 48 3. Datu Processirig Procedures c
Page 64 and 65: 50 3. Data Processitig Procedures c
Page 66 and 67: 52 3. Data Processirig Procedures s
Page 68 and 69: 54 3. Ihta Processing Procedures Se
Page 70 and 71: 56 3. htcr Processirig Procedures w
Page 72 and 73: 58 3. Data Processitig PrmedureLs i
Page 74 and 75: 60 3. Datu Processirig Procedures f
Page 76 and 77: 62 3. Data Processing Procedures Th
Page 78 and 79: 64 3. Dutct Processing Procedures m
Page 80 and 81:
66 3. Data Processing Procedures ch
Page 82 and 83:
68 3. Dutu Processing Procedures an
Page 84 and 85:
70 3. Data Processirig Procedures i
Page 86 and 87:
72 3. Dnta Processing Procedures co
Page 88 and 89:
74 3. Data Processing Procedures se
Page 90 and 91:
4. Seismic Ray Tracing for Minimum
Page 92 and 93:
78 4. Seismic Ray Tracing for Minim
Page 94 and 95:
80 4. Seismic Ruy Trucing for Minim
Page 96 and 97:
Page 98 and 99:
(1 84 4. Seismic Ray Tracing for Mi
Page 100 and 101:
Page 102 and 103:
88 4. Seismic Ray Tracirig for Mini
Page 104 and 105:
90 4. Seismic Ray Trucing .for Mini
Page 106 and 107:
92 4. Seismic Ruy Tracing for Minim
Page 108 and 109:
Page 110 and 111:
% 4. Seismic Ray Tracing for Minimu
Page 112 and 113:
Page 114 and 115:
100 4. Seismic Ray Tracing for Mini
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
106 5. Inversion and Optimization u
Page 122 and 123:
108 5. Inversion and Optimization G
Page 124 and 125:
110 5. Inversion and Optimization t
Page 126 and 127:
112 5. Inversion and Optimization n
Page 128 and 129:
114 5. Inversion and Optimization n
Page 130 and 131:
116 5. Inversion and Optimization B
Page 132 and 133:
118 5. In versiori nnd Optimization
Page 134 and 135:
120 5. Iwersioti arid Optirnizntior
Page 136 and 137:
122 5. Inversion and Optimization m
Page 138 and 139:
124 5. Inversion and Optimization i
Page 140 and 141:
126 5. Inversion criid Optimization
Page 142 and 143:
128 5. Inversiori niid Optimization
Page 144 and 145:
130 6. Methods of Data Analysk 6.1.
Page 146 and 147:
132 6. Methods of Data Analysis We
Page 148 and 149:
134 6. Methods of Data Analysis x*
Page 150 and 151:
136 6. Methods oj Data Analysis It
Page 152 and 153:
138 6. Methotls of Data Analysis te
Page 154 and 155:
140 6. Methods of Data Analysis pur
Page 156 and 157:
142 6. Methods of Data Analysis (a)
Page 158 and 159:
144 6. Methods qf Dcrtcr Analysis N
Page 160 and 161:
146 6. Methods of Dutcr Analysk imp
Page 162 and 163:
148 6. Methods of Data Analysis sho
Page 164 and 165:
150 6. Methods of Data Aizalysis tr
Page 166 and 167:
152 6. Methods of Data Analysis (6.
Page 168 and 169:
154 6. Methods of Data Analysis qua
Page 170 and 171:
156 6. Methods of Datu Analysls mag
Page 172 and 173:
158 6. Methods of Data Analysis 6.5
Page 174 and 175:
160 6. Methods of Data Analysis (6.
Page 176 and 177:
162 6. Methods of Data Analysis fro
Page 178 and 179:
7. General Applications Data from m
Page 180 and 181:
166 7. General Applications in ampl
Page 182 and 183:
168 7. General Applications Rangely
Page 184:
170 7. General Applications The inv
Page 213 and 214:
8.1. Seistnicit~ Pritterns 199 made
Page 215 and 216:
8.1. Seismicity Patterns 201 only p
Page 217 and 218:
8.1. Seismicit! Plitterrzs 203 betw
Page 219 and 220:
Keilis-Borok et al. (1980b) suggest
Page 221 and 222:
8.1. Srismic.itJ Ptrtterns 207 of t
Page 223:
8.2. Temporal V'iricrtions of Seism
Page 229 and 230:
8.3. Temporiil Vuriiitiotis qf Otli
Page 231 and 232:
8.3. TemporuI Variations of Other S
Page 233 and 234:
8.3. Temporal Vcrridoris of‘ Othe
Page 235 and 236:
8.3. Totnportrl Vtrritrtiotis of' O
Page 237 and 238:
9. Discussion Microearthquake studi
Page 239 and 240:
Automation usually does not reduce
Page 241 and 242:
Glossar? of' A bbreiqiations 227 da
Page 243 and 244:
Glossary of AbbrciTintions 229 said
Page 245 and 246:
References Acton, F. S. (1970). "Nu
Page 247 and 248:
References 23 3 Asada, T. ( 1957).
Page 249 and 250:
Rtjfcrcric-es 235 travel-time chang
Page 251 and 252:
Refererices 237 Cleary, J. R., Wrig
Page 253 and 254:
References Eaton, J. P. (1976). Tes
Page 255 and 256:
References 24 1 Francis, T. J. G.,
Page 257 and 258:
243 Hagiwarii. T., and Iwata. T. (1
Page 259 and 260:
R efereiices 245 Horner, R. B., Ste
Page 261 and 262:
References 247 Kagan, Y. Y., and Kn
Page 263 and 264:
Referetices 249 Kodama, K. P., and
Page 265 and 266:
25 1 Lin, M. T., Tsai, Y. B., and F
Page 267 and 268:
References 253 Mikumo, T., Otsuka,
Page 269 and 270:
R eferetices 255 Nordquist, J. M. (
Page 271 and 272:
Re feret ices 257 F'rothero, W. A.
Page 273 and 274:
259 Sauber. J., and Talwani, P. (19
Page 275 and 276:
References 26 1 Stephens, C. D., La
Page 277 and 278:
Keferetices 263 Tsujiura, M. (1978)
Page 279 and 280:
R ef ere1 ices croearthquake observ
show all

principles and applications of microearthquake networks

Create successful ePaper yourself

Delete template?

Save as template?