Moderate magnitude 4.6 earthquake at 9 km depth31 Jul 16:32 UTC: First to report: USGS after 33 seconds.Update Thu, 31 Jul 2025, 16:33Moderate earthquake of magnitude 4.6 just reported 4 miles north of Fontana, California, United StatesA magnitude 4.6 earthquake near Fontana, San Bernardino County, California, USA, was reported only 39 seconds ago by the United States Geological Survey, considered the key international and national agency that monitors seismic activity in the US. The earthquake occurred at a very shallow depth of 5.6 miles beneath the epicenter in the morning on Thursday, July 31st, 2025, at 9:32 am local time. The exact magnitude, epicenter, and depth of the quake might be revised within the next few hours or minutes as seismologists review data and refine their calculations, or as other agencies issue their report.Based on the preliminary seismic data, the quake was probably felt by many people in the area of the epicenter. It should not have caused significant damage, other than objects falling from shelves, broken windows, etc.In Fontana (pop. 212,700) located 4 miles from the epicenter, Rialto (pop. 103,100) 5 miles away, San Bernardino (pop. 216,100) 8 miles away, Colton (pop. 54,600) 8 miles away, Rancho Cucamonga (pop. 175,200) 10 miles away, and Upland (pop. 76,400) 13 miles away, the quake should have been felt as light shaking.Weak shaking might have been felt in Riverside (pop. 322,400) located 14 miles from the epicenter, and Ontario (pop. 171,200) 14 miles away.Other towns or cities near the epicenter where the quake might have been felt as very weak shaking include Los Angeles (pop. 3,898,700) located 47 miles from the epicenter.VolcanoDiscovery will automatically update magnitude and depth if these change and follow up if other significant news about the quake become available. If you're in the area, please send us your experience through our reporting mechanism, either online or via our mobile app. This will help us provide more first-hand updates to anyone around the globe who wants to know more about this quake.If you were or still are in this area during the quake help others with your feedback and report it here.Download the Volcanoes & Earthquakes app and get one of the fastest seismic alerts online: Android | iOSI didn't feel itI felt this quakeEarthquake detailsDate & timeJul 31, 2025 16:32:24 UTC - Local time at epicenterThursday, Jul 31, 2025, at 09:32 am (America/Los Angeles GMT -7)Statuspreliminary (automatic detection)Magnitude4.6Depth9 kmEpicenter latitude / longitude34.1532°N / 117.4243°WSan Bernardino County, California, United StatesSeismic antipode34.1532°S / 62.5757°EShaking intensityV Moderate shaking near epicenterFelt0 reportsPrimary data sourceUSGS (United States Geological Survey)Nearest volcanoLavic Lake (99 km / 62 mi)Weather at epicenter at time of quakeClear Sky 26.4°C (80 F), humidity: 46%, wind: 0 m/s (0 kts)Estimated seismic energy released5 x 1011 joules (139 megawatt hours, equivalent to 120 tons of TNT) | equivalent to ONE quake of magnitude 4.6 | about seismic energy41 seconds agoJul 31, 2025 16:32 GMT / Jul 31, 2025 09:32 am (Los Angeles time)Lat / Lng: 34.1532 / -117.4243: 6 km N of Fontana, CaliforniaSource: USGSDetail info | You felt it? - Report it!';storedMarkers.push(['quake-22010646',34.15320,-117.42430,'41 seconds ago: Mag. 4.6, 6 km N of Fontana, California',html,'quakes-6-24.png',25,25,12,12,125]); function mkRep(id,notFelt){var nFelt=notFelt||false;var src="https://www.volcanoesandearthquakes.com/app/earthquake-report.php?quakeId="+id;if(nFelt==true){src+="¬Felt=true";}window.open(src,"","status=0,toolbar=0,location=0,directories=0,menubar=0,resizable=1,scrollbars=1,height=400,width=350");} function locationHashChanged(e){-1!=e.oldURL.indexOf("#popupMap")&&closePopup()} window.onhashchange = locationHashChanged; function comment(e){var t=e.parentNode,a=(t.dataset.id,document.getElementById("commentForm"));"none"==a.style.display?(t.appendChild(a),a.style.display="block"):a.style.display="none"}function sendComment(e){var t=e.parentNode,a=t.parentNode.dataset.id,n=document.getElementById("commentContent"),p=n.value.trim();if(p){var o="id="+a+"&quakeId="+thisQuakeId;o+="&comment="+decodeURIComponent(p),mkRequest("//reports.volcanodiscovery.com/app/eqReportComment.php","post",o,function(e){e.responseText;alert("Thank you for submitting your comment!"),t.style.display="none",n.value=""})}}function flagReport(e){var t=e.parentNode.dataset.id;if(confirm("Report this as inappropriate?")){var a="id="+t+"&quakeId="+thisQuakeId+"&flagAsInappropriate=1";mkRequest("//reports.volcanodiscovery.com/app/eqReportComment.php","post",a,function(t){var a=t.responseText;alert(a),e.style.display="none"})}}function likeReport(e){var t="id="+e.parentNode.dataset.id+"&quakeId="+thisQuakeId+"&like=1";mkRequest("//reports.volcanodiscovery.com/app/eqReportComment.php","post",t,function(t){t.responseText;e.style.opacity=.5})}]]>[smaller] [bigger]Most recent quakes Top 20 past 24 hrs Quakes in the US CaliforniaNearby placesThe closest larger town where the quake might have been felt is Los Angeles, a city of 3.9 million people in the United States, in 76 km (47 mi) distance west of the epicenter. People likely experienced weak shaking there. Many smaller towns and villages are located closer to the epicenter and might have experienced stronger shaking.The following table shows some of the places that might have been affected (or not) by the shaking.DistancePlaceMax. shaking intensity(*)RegionCountry7 km (4 mi)S of epicenterFontana(pop: 212,700)V: ModerateSan Bernardino County, CaliforniaUnited States7 km (5 mi)SE of epicenterRialto(pop: 103,100)V: ModerateSan Bernardino County, CaliforniaUnited States10 km (6 mi)S of epicenterBloomington(pop: 23,900)IV: LightSan Bernardino County, CaliforniaUnited States13 km (8 mi)E of epicenterSan Bernardino(pop: 216,100)IV: LightCaliforniaUnited States13 km (8 mi)SE of epicenterColton(pop: 54,600)IV: LightSan Bernardino County, CaliforniaUnited States16 km (10 mi)W of epicenterRancho Cucamonga(pop: 175,200)IV: LightSan Bernardino County, CaliforniaUnited States17 km (10 mi)S of epicenterGlen Avon(pop: 20,200)IV: LightRiverside County, CaliforniaUnited States18 km (11 mi)S of epicenterRubidoux(pop: 34,300)IV: LightRiverside County, CaliforniaUnited States19 km (12 mi)SE of epicenterLoma Linda(pop: 24,000)IV: LightSan Bernardino County, CaliforniaUnited States20 km (12 mi)SW of epicenterMira Loma(pop: 21,900)IV: LightRiverside County, CaliforniaUnited States20 km (12 mi)E of epicenterHighland(pop: 54,900)IV: LightSan Bernardino County, CaliforniaUnited States21 km (13 mi)W of epicenterUpland(pop: 76,400)IV: LightSan Bernardino County, CaliforniaUnited States22 km (14 mi)S of epicenterRiverside(pop: 322,400)IV: LightCaliforniaUnited States23 km (14 mi)SW of epicenterOntario(pop: 171,200)IV: LightSan Bernardino County, CaliforniaUnited States25 km (15 mi)SW of epicenterEastvale(pop: 59,000)IV: LightRiverside County, CaliforniaUnited States25 km (15 mi)SE of epicenterRedlands(pop: 71,000)IV: LightSan Bernardino County, CaliforniaUnited States26 km (16 mi)W of epicenterMontclair(pop: 38,700)IV: LightSan Bernardino County, CaliforniaUnited States27 km (17 mi)SW of epicenterNorco(pop: 26,300)IV: LightRiverside County, CaliforniaUnited States28 km (17 mi)W of epicenterClaremont(pop: 36,300)IV: LightLos Angeles County, CaliforniaUnited States29 km (18 mi)SW of epicenterChino(pop: 85,600)IV: LightSan Bernardino County, CaliforniaUnited States30 km (19 mi)SE of epicenterMoreno Valley(pop: 204,200)IV: LightRiverside County, CaliforniaUnited States32 km (20 mi)W of epicenterPomona(pop: 153,300)IV: LightLos Angeles County, CaliforniaUnited States32 km (20 mi)W of epicenterLa Verne(pop: 32,700)IV: LightLos Angeles County, CaliforniaUnited States32 km (20 mi)N of epicenterHesperia(pop: 93,300)IV: LightSan Bernardino County, CaliforniaUnited States34 km (21 mi)S of epicenterCorona(pop: 164,200)IV: LightRiverside County, CaliforniaUnited States36 km (22 mi)SW of epicenterChino Hills(pop: 78,300)IV: LightSan Bernardino County, CaliforniaUnited States36 km (22 mi)SW of epicenterChino Hills(pop: 78,300)IV: LightSan Bernardino, CaliforniaUnited States36 km (22 mi)W of epicenterSan Dimas(pop: 34,600)IV: LightLos Angeles County, CaliforniaUnited States38 km (23 mi)E of epicenterYucaipa(pop: 53,300)IV: LightSan Bernardino County, CaliforniaUnited States38 km (24 mi)W of epicenterDiamond Bar(pop: 56,900)IV: LightLos Angeles County, CaliforniaUnited States41 km (25 mi)W of epicenterGlendora(pop: 52,000)IV: LightLos Angeles County, CaliforniaUnited States43 km (27 mi)W of epicenterCovina(pop: 49,000)III: WeakLos Angeles County, CaliforniaUnited States44 km (28 mi)N of epicenterVictorville(pop: 122,200)III: WeakSan Bernardino County, CaliforniaUnited States44 km (28 mi)NE of epicenterApple Valley(pop: 72,200)III: WeakSan Bernardino County, CaliforniaUnited States45 km (28 mi)SE of epicenterPerris(pop: 75,000)III: WeakRiverside County, CaliforniaUnited States46 km (29 mi)SW of epicenterYorba Linda(pop: 68,000)III: WeakOrange County, CaliforniaUnited States48 km (30 mi)W of epicenterWest Covina(pop: 108,500)III: WeakLos Angeles County, CaliforniaUnited States50 km (31 mi)W of epicenterBaldwin Park(pop: 77,100)III: WeakLos Angeles County, CaliforniaUnited States76 km (47 mi)W of epicenterLos Angeles(pop: 3,898,700)III: WeakCaliforniaUnited States613 km (381 mi)NW of epicenterSacramento(pop: 490,700)I: Not feltCaliforniaUnited StatesNotes:(*) Shaking intensity according to the Modified Mercalli Intensity Scale (MMI) and estimated using seismic models.User-reports for this quakeThere are no user reports for this quake yet.If you felt it, be the first to report it!Compare Quake DataData for the same earthquake as reported by different agenciesThe more agencies report about the same quake and post similar data, the more confidence you can have in the data. It takes normally up to a few hours until earthquake parameters are calculated with near-optimum precision.MagDepthTime GMT2025-07-31EpicenterAgency4.69 km5.6 mi16:32:246 km N of Fontana, CaliforniaUSGS (United States Geological Survey)Aftershocks for this quakeNo aftershocks have been recorded so far. When aftershocks are detected, we will update this section.What are aftershocks?Larger earthquakes (above magnitude 5 or so) such as this one are usually followed by smaller ones known as aftershocks that occur in the same area during the days, weeks, months or even years after the main shock.[More info]What about this quake?Based on its magnitude, the fault that was active during the quake likely ruptured beneath a surface area of approximately 4 km2 (2 square miles) as a first-order estimate. The length of the rupture zone thus was probably around 3 km (2 mi).[More info]Recorded aftershocks, latest first (0 quake)Jul 31, 2025 09:32 am (Los Angeles)41 seconds ago4.69 km0 km - This quake4.3 mi N of Fontana, San Bernardino County, California, United StatesMain Shock (this quake)MoreMap of aftershocksEarthquake statisticsAverage number of earthquakesBased on data from the past 55 years and our earthquake archive back to 1900, there are about 7,600 quakes on average per year in the area near the epicenter of this quake (within 100 km/61 mi):Mag. 7 or higher: 0.02 quakes per year (or 1 quake every 62.5 years)Mag. 6 or higher: 0.1 quakes per year (or 1 quake every 10.4 years)Mag. 5 or higher: 0.64 quakes per year (or 1 quake every 1.6 years)Mag. 4 or higher: 3.3 quakes per yearMag. 3 or higher: 25.6 quakes per yearMag. 2 or higher: 260 quakes per year (or 21.6 quakes per month)Mag. 1 or higher: 2,700 quakes per year (or 7.4 quakes per day)The area where this quake occurred has a very high level of seismic activity. It has had at least 2 quakes above magnitude 7 since 1900, which suggests that larger earthquakes of this size occur infrequently, probably on average approximately every 60 to 65 years.Number of quakes per yearPrevious quakes in the same area of this earthquake