Llocity Gradients in the Continental Crust from Head-wave Amplitudes
نویسنده
چکیده
.1'. ii-ari. f'mnM vrlority »»rodirnl« in A rcfrn'lint' liorixon hnve « pronoimml rfTiri on «ho .-(■•I'I il imiili'iul.-i of licml wnvra. Nrentivc vrWuy urndirnt» nml niulnstiiily ('.»') nMilt in ;i >iinil;ir nuifililnite drr.iy with «lislnnro fur nirrow-bnmlwidih il.iln. Pcwjlirc vrlority ifi.iilii n(» n Mill in n net nniplituilc cnin «itli fliiliincft compircd with tlwhr.-id w.ivo from n liiiiii'iri nrniM, pcrfmllv cl.ii-lic rrfrnclor. Wnvo-llirorplicnl exprr^ions fo.(lic»e pffrcl« npplicrf In i>iiMi.«liri| «mpliliifle dnla for Ihe mnjor rmstnl rrfrnction brflnchM.' P, nnH /**, «HRRCH HUH 1I11'cr.iniiir' rriwl in llio Bnsin nnd Hanpo provinrr hnn rillirr ncc.itiVA vislocily grndirnl» of (lin ord"T of 10' km/sre/km or nn nnclnslie Q of the order of 400, «-hcrciu tho 'granilic' rnist in llir fftern United Slntrs and on llic California const )ms .«lichlly positive velocity uridiont». Piinil.'irly, the 'liiis.iliir' intrrmodintc l.iycr nppenrs to Imvo n nrcnlivr Kcndicnt of the ordrr of 10 ' «"c" linder the Snake Hivcr plain nnd null or clicMly positive grndicnl« irndrr Lake Superior and Mi^issippi. Velocity cradii lit« infirnd fiom laboratory inenmire» rmniH on Rranito and haue ißneous rocks, together with imldishcd geothcrmal gradients, arc Kcnrriiliy conaistcnt with the gradicoU inferred from amplitude data.
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