Magnitude of the 1920 Haiyuan earthquake reestimated using seismological and geomorphological methods
Reported magnitudes ranging between 7.8 and 8.7 highlight a confusion about the true size of the 1920 Haiyuan earthquake, the largest earthquake recorded in the northeast Tibetan Plateau. We compiled a global data set of previously unlooked‐at historical seismograms and performed modern computationa...
| Main Authors: | , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
American Geophysical Union
2020
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| _version_ | 1797072213548990464 |
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| author | Ou, Q Kulikova, G Yu, J Elliott, A Parsons, B Walker, R |
| author_facet | Ou, Q Kulikova, G Yu, J Elliott, A Parsons, B Walker, R |
| author_sort | Ou, Q |
| collection | OXFORD |
| description | Reported magnitudes ranging between 7.8 and 8.7 highlight a confusion about the true size of the 1920 Haiyuan earthquake, the largest earthquake recorded in the northeast Tibetan Plateau. We compiled a global data set of previously unlooked‐at historical seismograms and performed modern computational analyses on the digitized seismic records. We found the epicenter to be near Haiyuan town and obtained a moment magnitude of MW=7.9±0.2. Following traditional approaches, we obtained mB=7.9±0.3 with data from 21 stations and MS(20)=8.1±0.2 with data from three stations. Geomorphologically, we mapped the surface rupture and horizontal offsets on high‐resolution Pleiades satellite and drone imagery that covered the entire western and middle sections of the 1920 Haiyuan earthquake rupture and compiled offsets reported on the eastern section from field measurements in the 1980s. Careful discrimination between single‐event and cumulative offsets suggests average horizontal slips of 3.0±1.0 m on the western section, 4.5±1.5 m on the middle section, and 3.5±0.5 m on the eastern section, indicating a total moment magnitude of MW=7.8±0.1. Thus, the seismological and geomorphological results agree within the uncertainties, a weighted average giving a moment magnitude of MW=7.9±0.2 for the 1920 Haiyuan earthquake. It is likely that earthquake magnitudes based on the historical M were systematically overestimated. |
| first_indexed | 2024-03-06T23:04:28Z |
| format | Journal article |
| id | oxford-uuid:634eb9db-f2d3-40bf-a18d-1351e7cd2890 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T23:04:28Z |
| publishDate | 2020 |
| publisher | American Geophysical Union |
| record_format | dspace |
| spelling | oxford-uuid:634eb9db-f2d3-40bf-a18d-1351e7cd28902022-03-26T18:12:07ZMagnitude of the 1920 Haiyuan earthquake reestimated using seismological and geomorphological methodsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:634eb9db-f2d3-40bf-a18d-1351e7cd2890EnglishSymplectic ElementsAmerican Geophysical Union2020Ou, QKulikova, GYu, JElliott, AParsons, BWalker, RReported magnitudes ranging between 7.8 and 8.7 highlight a confusion about the true size of the 1920 Haiyuan earthquake, the largest earthquake recorded in the northeast Tibetan Plateau. We compiled a global data set of previously unlooked‐at historical seismograms and performed modern computational analyses on the digitized seismic records. We found the epicenter to be near Haiyuan town and obtained a moment magnitude of MW=7.9±0.2. Following traditional approaches, we obtained mB=7.9±0.3 with data from 21 stations and MS(20)=8.1±0.2 with data from three stations. Geomorphologically, we mapped the surface rupture and horizontal offsets on high‐resolution Pleiades satellite and drone imagery that covered the entire western and middle sections of the 1920 Haiyuan earthquake rupture and compiled offsets reported on the eastern section from field measurements in the 1980s. Careful discrimination between single‐event and cumulative offsets suggests average horizontal slips of 3.0±1.0 m on the western section, 4.5±1.5 m on the middle section, and 3.5±0.5 m on the eastern section, indicating a total moment magnitude of MW=7.8±0.1. Thus, the seismological and geomorphological results agree within the uncertainties, a weighted average giving a moment magnitude of MW=7.9±0.2 for the 1920 Haiyuan earthquake. It is likely that earthquake magnitudes based on the historical M were systematically overestimated. |
| spellingShingle | Ou, Q Kulikova, G Yu, J Elliott, A Parsons, B Walker, R Magnitude of the 1920 Haiyuan earthquake reestimated using seismological and geomorphological methods |
| title | Magnitude of the 1920 Haiyuan earthquake reestimated using seismological and geomorphological methods |
| title_full | Magnitude of the 1920 Haiyuan earthquake reestimated using seismological and geomorphological methods |
| title_fullStr | Magnitude of the 1920 Haiyuan earthquake reestimated using seismological and geomorphological methods |
| title_full_unstemmed | Magnitude of the 1920 Haiyuan earthquake reestimated using seismological and geomorphological methods |
| title_short | Magnitude of the 1920 Haiyuan earthquake reestimated using seismological and geomorphological methods |
| title_sort | magnitude of the 1920 haiyuan earthquake reestimated using seismological and geomorphological methods |
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