زلزال بطيء
| جزء من سلسلة مقالات عن الزلازل |
|---|
| الأنواع |
|
هزة سابقة • هزة تابعة • الدفع الأعمى مزدوج • بين الصفائح • داخل الصفيحة الدفع الهائل • مثارة عن بعد • بطيء تحت الماء • قص فائق تسونامي • Earthquake swarm |
| الأسباب |
| حركة الفوالق • نشاط بركاني • Induced seismicity |
| الخصائص |
|
مركز الزلزال • بؤرة الزلزال • منطقة الظل موجة سيزمية • الموجة پي • الموجة إس |
| القياس |
|
مقاييس زلزالية • السيزموگراف مقياس مدة الزلزال |
| التنبؤ |
|
اللجنة المنسقة لتوقع الزلازل حساس بالزلازل |
| أخرى |
|
فصم موجة القص • معادلة أدمز-وليامسون مناطق فلين-إنگدال • هندسة الزلزال Seismite • علم الزلازل |
الزلزال البطئ slow earthquake، هو حدث شبيه بالزلزال، ينطلق طاقة لفترة تتراوح من ساعات إلى شهور، أكبر من الدقائق والثواني التي يستغرقها الزلزال التقليدي. First detected using long term strain measurements,[1] most slow earthquakes now appear to be accompanied by fluid flow and related tremor,[2] which can be detected and approximately located using seismometer data filtered appropriately (typically in the 1–5 Hz band). That is, they are quiet compared to a regular earthquake, but not "silent" as originally described.[3] They rupture anywhere between 1 to 1.5 kilometres (0.62 to 0.93 mi) per second as compared to 3 kilometres (1.9 mi) per second for regular earthquakes.[4] يمكن للزلازل البطيئة أن تتسبب في موجات هائلة من التسونامي.[4]
من المحتمل أن تقع الزلازل البطيئة بسبب a variety of stick-slip and creep processes intermediate between asperity-controlled brittle failure and ductile flow.[بحاجة لمصدر] They are best documented from intermediate crustal levels of certain subduction zones (especially those that dip shallowly—SW Japan, Cascadia, Chile), but appear to occur on other types of fault as well, notably strike-slip plate boundaries such as the San Andreas fault and "mega-landslide" normal faults on the flanks of volcanos.[بحاجة لمصدر]
Slow earthquakes can be episodic, and therefore somewhat predictable, a phenomenon termed episodic tremor and slip or ETS in the literature. Several slow earthquake events around the world appear to have triggered major, damaging seismic earthquakes in the shallower crust (e.g., 2001 Nisqually, 1995 Antofagasta). Conversely, major earthquakes trigger "post-seismic creep" in the deeper crust and mantle.[5] Slow earthquakes therefore constitute a "missing link" between deep earth processes and their typically more intermittent and catastrophic effects on the Earth's surface. While it is doubtful that slow earthquakes will ever provide a robust tool for earthquake prediction, their relative regularity does serve to remind the public that the forces that generate earthquakes are ongoing and inexorable.
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المصادر
- ^ Michael R. Forrest. "Slow Earthquakes". Scec.org. Retrieved 2010-05-05.
- ^ [1][dead link]
- ^ Timothy I. Melbourne and Frank H. Webb (2003-06-20). "GEOPHYSICS: Enhanced: Slow But Not Quite Silent - Melbourne and Webb 300 (5627): 1886 - Science". Sciencemag.org. doi:10.1126/science.1086163. Retrieved 2010-05-05.
- ^ أ ب Mustain, Andrea (2011-03-18). "Sneaky 'Slow' Earthquakes Can Cause Outsize Tsunamis". LiveScience & UurAmazingPlanet. Retrieved 2011-03-26.
{{cite web}}: Unknown parameter|month=ignored (help)CS1 maint: date and year (link) - ^ Timothy I. Melbourne and Frank H. Webb. "Surface Creep Measurements from a Slow Earthquake on the San Andreas Fault Using InSAR". Seismo.berkeley.edu. Retrieved 2010-05-05.