[ { "id": "authors:23z1g-mzq46", "collection": "authors", "collection_id": "23z1g-mzq46", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131125-100503846", "type": "book", "title": "A Dislocation Model of the 1994 Northridge, California, Earthquake Determined From Strong Ground Motions", "author": [ { "family_name": "Wald", "given_name": "David J.", "clpid": "Wald-D-J" }, { "family_name": "Heaton", "given_name": "Thomas H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" } ], "abstract": "A preliminary rupture model of the 1994 Northridge, California earthquake, determined\nfrom strong motion waveform inversion and analysis, is presented. The fault rupture plane\nchosen is based on the distributions of aftershocks and teleseismic surface-wave and bodywave\npoint-source solutions. The fault strikes 122\u00b0, dips 42\u00b0, and has a slip vector of 109\u00b0.\nThe average slip is about 1.2 meters over the rupture area and the peak slip reaches nearly\n4 meters. Our estimate of the seismic moment is 1.2 \u00b1 0.2 x 10^(26) dyne-cm. The area of\nrupture is small relative to the aftershock dimensions and is approximately 14 km along\nstrike (west-northwest from the hypocenter) and nearly 20 km in the updip direction. There\nis little indication of slip shallower than about 7 km.\n\n\nThe up-dip, near-source strong-motion velocity waveforms show two distinct, large S-wave\narrivals 2-3 sec apart (as do the teleseismic P waves), indicating separate source subevents.\nAn along strike (west-northwest) subevent separation of about 8 km is most consistent with\nthe observation that the two main arrivals are separated more in time to the south and\nsoutheast (about 4.5 sec at Stone Canyon Reservoir and Sherman Oaks, for example), than\nat northern azimuths. The interpretation of secondary arrivals observed at more distant\nstations to the south and southeast (e.g., Santa Monica) is more tenuous, since several of\nthe aftershocks recorded there indicate later arrivals as well. However, a secondary source\ncontribution is expected based on our model of the closer stations.\n\n\nAfter placing these constraints on the general nature of the rupture, we predict the characteristics\nof the long-period (1-10 sec) ground velocities over a grid of stations covering the\nnear-source region. This exercise provides a basis for separating the effects of source radiation\n(dominated by radiation pattern and directivity) from the complex waveform modifications\ndue to wave-propagation and site response.", "publisher": "U.S. Geological Survey", "publication_date": "1994" }, { "id": "authors:t8njg-4mw21", "collection": "authors", "collection_id": "t8njg-4mw21", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121127-093130762", "type": "book", "title": "Southern California Seismographic Network; report to the U.S. Geological Survey, August 21, 1990", "author": [ { "family_name": "Hauksson", "given_name": "Egill", "orcid": "0000-0002-6834-5051", "clpid": "Hauksson-E" }, { "family_name": "Jones", "given_name": "Lucile", "orcid": "0000-0002-2690-3051", "clpid": "Jones-L-M" }, { "family_name": "Mori", "given_name": "James", "clpid": "Mori-Jim" }, { "family_name": "Clayton", "given_name": "Robert", "orcid": "0000-0003-3323-3508", "clpid": "Clayton-R-W" }, { "family_name": "Heaton", "given_name": "Thomas", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" }, { "family_name": "Kanamori", "given_name": "Hiroo", "orcid": "0000-0001-8219-9428", "clpid": "Kanamori-H" }, { "family_name": "Helmberger", "given_name": "Don", "clpid": "Helmberger-D-V" } ], "abstract": "On August 21, 1990, the U. S. Geological Survey held a meeting to\nreview the status of regional seismic networks in the United States. The\npurpose of the meeting was to provide information to the U.S.G.S. to assist\nthem in setting priorities for future funding of seismic networks in a time\nof increasingly tight budgets. Each of the networks was therefore asked to\nprepare a report describing their goals and accomplishments. Three\nspecific questions were raised: how the objectives of the network have\nbeen met, the potential for future productivity and opportunities for\nadditional funding.", "doi": "10.3133/ofr9138", "publisher": "U.S. Geological Survey", "publication_date": "1991-01" }, { "id": "authors:em1p6-gvy30", "collection": "authors", "collection_id": "em1p6-gvy30", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121127-080857098", "type": "book", "title": "National Seismic System Science Plan", "author": [ { "family_name": "Heaton", "given_name": "Thomas H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" }, { "family_name": "Anderson", "given_name": "Don L.", "clpid": "Anderson-D-L" }, { "family_name": "Arabasz", "given_name": "Walter J.", "clpid": "Arabasz-W-J" }, { "family_name": "Buland", "given_name": "Ray", "clpid": "Buland-R" }, { "family_name": "Ellsworth", "given_name": "William L.", "clpid": "Ellsworth-W-L" }, { "family_name": "Hartzell", "given_name": "Stephen H.", "clpid": "Hartzell-S-H" }, { "family_name": "Lay", "given_name": "Thorne", "orcid": "0000-0003-2360-4213", "clpid": "Lay-T" }, { "family_name": "Spudich", "given_name": "Paul", "clpid": "Spudich-P" } ], "abstract": "Recent developments in digital communication and seismometry\nare allowing seismologists to propose revolutionary\nnew ways to reduce vulnerability from earthquakes, volcanoes,\nand tsunamis, and to better understand these\nphenomena as well as the basic structure and dynamics of the\nEarth. This document provides a brief description of some of\nthe critical new problems that can be addressed using modem\ndigital seismic networks. It also provides an overview of existing\nseismic networks and suggests ways to integrate these\ntogether into a National Seismic System.\nA National Seismic System will consist of a number of\ninterconnected regional networks (such as southern California,\ncentral and northern California, northeastern United\nStates, northwestern United States, and so on) that are jointly\noperated by Federal, State, and private seismological research\ninstitutions. Regional networks will provide vital information\nconcerning the hazards of specific regions. Parts of these networks\nwill be linked to provide uniform rapid response on a\nnational level (the National Seismic Network).\nA National Seismic System promises to significantly\nreduce societal risk to earthquake losses and to open new areas\nof fundamental basic research. The following is a list of some\nof the uses of a National Seismic System.", "doi": "10.3133/cir1031", "publisher": "Dept. of the Interior, U.S. Geological Survey", "publication_date": "1989" }, { "id": "authors:81p7b-5px85", "collection": "authors", "collection_id": "81p7b-5px85", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121127-084238485", "type": "book", "title": "Estimation of strong ground motions from hypothetical earthquakes on the Cascadia subduction zone, Pacific Northwest", "author": [ { "family_name": "Heaton", "given_name": "Thomas H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" }, { "family_name": "Hartzell", "given_name": "Stephen H.", "clpid": "Hartzell-S-H" } ], "abstract": "Strong ground motions are estimated for the Pacific Northwest\nassuming that large shallow subduction earthquakes, similar to those\nexperienced in southern Chile, southwestern Japan, and Colombia, may\nalso occur on the Cascadia subduction zone. Fifty-six strong motion\nrecordings from twenty-five subduction earthquakes of M_S \u2265 7.0 are used\nto estimate the response spectra that may result from earthquakes M_w < 8\n1/4 Large variations in observed ground motion levels are noted for a\ngiven site distance and earthquake magnitude. When compared with\nmotions that have been observed in the western United States, large\nsubduction zone earthquakes produce relatively large ground motions at\nsurprisingly large distances. An earthquake similar to the 22 May 1960\nChilean earthquake (M_w 9.5) is the largest event that is considered to\nbe plausible for the Cascadia subduction zone. This event has a moment\nwhich is two orders of magnitude larger than the largest earthquake for\nwhich we have strong motion records. The empirical Green's function\ntechnique is used to synthesize strong ground motions for such giant\nearthquakes. Observed teleseismic P-waveforms from giant earthquakes\nare also modeled using the empirical Green's function technique in order\nto constrain model parameters. The teleseismic modeling in the period\nrange of 1.0 to 50 sec strongly suggests that fewer Green's functions\nshould be randomly summed than is required to match the long-period\nmoments of giant earthquakes. It appears that a large portion of the\nmoment associated with giant earthquakes occurs at very long periods\nthat are outside the frequency band of interest for strong ground\nmotions. Nevertheless, the occurrence of a giant earthquake in the\nPacific Northwest may produce quite strong shaking over a very large\nregion.", "doi": "10.3133/ofr86328", "publisher": "U.S. Dept. of the Interior, Geological Survey", "publication_date": "1986" }, { "id": "authors:1yqb6-qs029", "collection": "authors", "collection_id": "1yqb6-qs029", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121128-134808528", "type": "book", "title": "Accelerograms from the Mammoth Lakes, California earthquake sequence of May-July, 1980 recorded on a temporary array", "author": [ { "family_name": "Moslem", "given_name": "Kaazem", "clpid": "Moslem-K" }, { "family_name": "Amini", "given_name": "Ali", "clpid": "Amini-A" }, { "family_name": "Kontic", "given_name": "Branko", "clpid": "Kontic-B" }, { "family_name": "Anderson", "given_name": "John G.", "clpid": "Anderson-J-G" }, { "family_name": "Heaton", "given_name": "Thomas H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" } ], "abstract": "The Mammoth Lakes California earthquake sequence consisted of three\nearthquakes of M > 6, and numerous smaller shocks. After the first of the\nM > 6 events, a field crew was mobilized to install, on a temporary basis,\nseven strong motion accelerographs which were borrowed from other less urgent\napplications. A total of 169 accelerograms were recorded, including multiple\nrecordings from one event with M = 6.3, three more events with M > 5.0, and\nmultiple recordings of 21 separate aftershocks with M > 3.", "publisher": "University of Southern California", "publication_date": "1983-02" } ]