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New measurements tell a bigger story. The weakening reaches far past the visible crack \u2013 tens of miles past it \u2013 and it quietly governs how fast whole landscapes wear down.<\/p>\n
The hidden reach<\/p>\n
A global study now puts numbers on that reach. Drawing on more than 1,700 measurements of how fast rock wears away in river basins worldwide, researchers found that erosion<\/a> speeds up sharply near active faults and tapers off with distance.<\/p>\n The effect stretches to roughly 60 miles from the largest fault systems. <\/p>\n Geologist Boontigan Kuhasubpasin led the work as a doctoral researcher at the University of California, Los Angeles (UCLA<\/a>).<\/p>\n Damage runs hottest within about nine miles of a fault, then fades to almost nothing near that 60-mile edge. <\/p>\n Until now, most evidence kept the wreckage within a mile of the fault itself. No one had traced it spreading this far.<\/p>\n Evidence from the rivers<\/p>\n The clue came from rivers. As rock breaks down and washes downstream, the sediment carries a record of how fast the land upstream is being stripped away.<\/p>\n Hidden in that sediment is a rare, natural form of beryllium that builds up in rock left at the surface. <\/p>\n The longer the rock bakes in the open, the more it collects, so its level reveals how fast the surface has worn down.<\/p>\n Tally that across more than 1,700 basins, lay it over maps of faults<\/a> and past ground shaking, and the pattern jumped out. <\/p>\n Rock near faults eroded far more quickly because the ground was weakest closest to the fault.<\/p>\n Forces that strain the land<\/p>\n Plenty of forces wear down a landscape. Rainfall loosens slopes; soft rock crumbles faster than hard. <\/p>\n To find which force dominated, the team fed everything into machine-learning models and asked them to rank the contenders.<\/p>\n Distance to a fault came out on top, beating rainfall and rock type across much of the restless, quake-prone world. <\/p>\n Adding a measure of how hard the ground shakes sharpened the models even more.<\/p>\n That ordering surprised the researchers. Climate and rock type have long been treated as the main controls on erosion. <\/p>\n Watching a fault outrank them, basin after basin, left the quakes as the likely culprit.<\/p>\n What shaking does<\/p>\n How a fault weakens rock so far from its edge is harder to pin down. The team cannot watch it happen underground, so the mechanism is an informed read, not a direct sighting.<\/p>\n Their best explanation is the shaking. Every quake jolts the surrounding rock. Over thousands of years, that repeated battering likely opens tiny cracks called microfractures.<\/p>\n \u201cRepeated shaking can open microfractures, weaken contacts between mineral grains and reduce the strength of near-surface rock,\u201d said study co-author Carolina Lithgow-Bertelloni, a UCLA earth scientist.\u00a0<\/p>\n Once loosened, the rock becomes an easy target. Rivers cut down faster, hillsides slump into landslides, and weathering eats at the stone. <\/p>\n Slower waves and quicker erosion<\/p>\n A worldwide pattern is persuasive, but the team wanted to test it on familiar ground. <\/p>\n The researchers zoomed in on Southern California, where the San Andreas Fault<\/a> and its many neighbors keep the crust in constant motion.<\/p>\n There, the rock near faults behaved just as the global data predicted. Seismic waves slowed as they passed through the fractured rock near the faults, revealing extensive damage. <\/p>\n Those same areas also eroded more quickly, reinforcing the link between repeated earthquake shaking and weakened rock.<\/p>\n The overlap of slower waves and quicker erosion is hard to pin on anything else. Here, faults were lifting the terrain and weakening the rock beneath it at once.<\/p>\n Earthquakes leave lasting scars<\/p>\n For a long time, faults earned their reputation mainly for building mountains. This study shows they also govern how fast the surrounding land comes apart, over distances no one had measured.<\/p>\n \u201cThis provides a physical explanation for why erosion is more efficient in tectonically active regions,\u201d the team wrote. <\/p>\n That changes how scientists read quake-prone country. Worn landscapes near faults may have been carved less by rain or rock type and more by centuries of shaking.\u00a0<\/p>\n The payoff lands in hazard planning. If weakened rock reaches dozens of miles past a fault, then landslide zones, reservoirs filling with sediment, and the slow build of mountains all stretch wider than current maps assume. <\/p>\n Quakes already move huge volumes of rock downhill, as one analysis<\/a> of quake-driven slides found.<\/p>\n None of this erases rain or rock type. They still shape the landscape. But this study suggests earthquakes have been doing far more of the work than anyone realized. <\/p>\n A fault\u2019s influence reaches far beyond the visible fracture, leaving weaker rock and faster erosion across a much broader swath of the landscape.<\/p>\n The study is published in the journal Science<\/a>.<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"An earthquake strikes, the ground rips open along a fault, and the worst of the damage sits right…\n","protected":false},"author":2,"featured_media":523412,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[61,60,82],"class_list":["post-523411","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ie","tag-ireland","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/523411","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=523411"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/523411\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/523412"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=523411"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=523411"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=523411"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}