Sunday, October 12, 2014
Update on this year's El Nino
"wimpy El Nino" conclusion! For us in the Pacific Northwest, it means that predictions for the winter basically can't be done, unless the El Nino suddenly strengthens.
Wednesday, October 8, 2014
Super Typhoon Vongfong headed for Okinawa
The largest typhoon of the calendar year is heading toward Okinawa. It is the fifth super typhoon of the year (150 km sustained winds or higher). It is the strongest storm since Typhoon Haiyan, which killed over 5,000 people in the Phillipines in November, 2013. It is following on the heels of Thyphoon Fanphone which struck near Tokyo just a few days ago.
Forecast from The Weather Channel |
7:30 a.m. Thursday, Oct. 9, Japan time: Not good, campers. Joint Typhoon Warning Center’s latest forecast track depicts a slightly closer turn by Vongfong to Okinawa late Saturday into Sunday. Closest point of approach now projected at 62 miles east-northeast at about 10 p.m. Saturday.
That changes the wind forecast timeline for Okinawa given Vongfong’s latest forecast proximity to Okinawa. Here’s the latest from Kadena Air Base’s 18th Wing Weather Flight:
- 29-mph crosswinds at Kadena, from 3 p.m. Friday.
- Sustained 40-mph winds, from 2 a.m. Saturday.
- Sustained 58-mph winds, from 11 a.m. Saturday.
- Maximum 63-mph winds and 74-mph gusts at Kadena, maximum 81-mph sustained winds and 104-mph gusts over northeastern Okinawa at 11 p.m. Saturday.
- Winds diminishing below 58 mph sustained, from 6 a.m. Sunday.
- Winds diminishing below 40 mph sustained, from 11 a.m. Sunday.
- 29-mph crosswinds no longer occurring at Kadena, from 11 a.m. Tuesday.
All of this could change, since there’s a large disparity among dynamic model guidance. JTWC forecast tracks tend to fall toward center of model consensus. We’ll see how things go in the next couple of days. PST will keep this under finger.
It is likely to to hit Honshu on Monday into Tuesday as a Category 1 tropical storm. Some areas that will be hit experienced up to 10" of rain from Phanfone, so the danger of flash flooding and mudslides along the eastern coast of Japan is high, with some areas getting an estimated 8-12" of rain.
The conditions that contributed to the rapid intensification were very low vertical wind shear, high outflow winds spreading away from the center and thus encouraging upward motion of air and thunderstorms, and warm western Pacific water. The estimated central pressure is about 900 millibars.
Saturday, September 27, 2014
Ontake, Japan, erupts
Ontake erupts. Photo by andreijejune as cited above. The eruption started around 11:53 a.m. Saturday, local time (in spite of the setting in the caption above) |
A few hours ago (Saturday), Mount Ontake 155 miles west of Tokyo, erupted, sending a steamy ash plume high into the sky. It last erupted in 2007. News is conflicting about the casualties, but at least one person has been killed, thirty people have been injured and the Japanese are organizing to rescue an unknown number (reports vary between 41 and 200?) people who were climbing on the mountain. As much as 20" of ash has been reported on the ground near the summit, and Japanese authorities are issuing an alert to stay at least 4 miles away from the summit. The alert level is "3" meaning "do not approach the volcano." Ash is reported to have gone 3 kilometers down the mountain in a pyroclastic flow. There are a number of YouTube videos showing the eruption through cameras held by hikers. Here's one.
From the Kinja Space site cited in the text and the twitter user identified above. |
Ontake is the second highest volcano in Japan, at 3,067 meters, second to Mount Fuji. There is a nice description of the tectonic setting of Ontake, as well as a collection of eyewitness accounts, at Kinja Space, authored by Mika McKinnon, from which I take much of the following discussion. The author of this blog nicely states that because of geochemical differences in the magmas, volcanoes over oceanic tectonic plates typically have a relatively low abundance of silica (SiO2) and are fairly fluid allowing their gases to escape rather gently (think Iceland, Hawaii). When the eruptions do turn explosive, it is usually because the magma has interacted with groundwater or ice. Volcanoes that are rich in silica are viscous and gases don't escape easily, leading to conditions that produce explosive eruptions. Such volcanoes usually are found where oceanic and continental plates intersect. The Pacific Ring of fire that stretches up from South America, through western North America and around to Japan is such a setting and eruptions here can be very dangerous. Eruptions of these volcanoes produce flying rocks, volcanic bombs, and hot pyroclastic flows. The movies of the survivors are lucky to be alive.
Ontake had a minor eruption involving water (phreatic) in 2007, but the last major eruption stretched from October 1979-April 1980. In spite of claims that it had erupted in 1892 and 774 AD, detailed examination of the records suggest that this is not true and that it had not erupted prior to the 1979-1980 sequence in recorded history, which is a long time in Japan. Local volcanologists/seismologists Koshun Yamaoka and Shigeo Aramaki are suggesting that the billowing white clouds seen in the eyewitness photos suggest that this is a phreatic eruption. The possibility that phreatic eruptions are signaling heating of groundwater by rising magma leaves open the scenario of a major magmatic eruption like that of Mount St. Helens that began about 4 hours after the 1980 March-April lateral blast.
Labels:
ash plume,
Ontake,
phreatic,
volcanic eruption
Tuesday, September 16, 2014
Mayon and Bardarbunga volcanoes.
Mayon volcano, copyright Tom Tam shot from Lingnon hill in Daraga Town near the volcano and his home |
The volcanic activity is being actively reported on Wiki here, and here is the link to the Philippine Institute of Volcanology and Seismology, PHILVOLCS. The monitoring network has detected 39 rockfall events that are "ascribed to incipient breaching of the growing summit lava dome." Continuing seismicity indicates either magma intrusion or volcanic gas activity, and there is sufficient magma in the summit crater to cause a red glow. PHILVOCS has raised the alert level to Level 3, stating that a hazardous eruption is "possible within weeks." A Permanent Danger Zone extends out to a 6 km radius, and an Extended Danger Zone to 7 km. These are being evacuated because of danger of rockfalls, landslides, and lava/ash/mud flows. (Level 3 is the third highest level of alert, following "eruption" and "imminent eruption.")
Bardarbunga in Iceland continues to be active seismically and as of a flyover of the Holuhraun fissure on Sept. 12, about 200 cu meters of magma per second are erupting. Lava is flowing nearly 20 km from the vent.
Labels:
Bardarbunga,
Holuhraun,
lava dome,
Mayon,
PHILVOLCS,
seismicity
Wednesday, September 10, 2014
Major solar storm, alert for a CME, coronal mass ejection
Sunspot region 2158, the source of a solar flare today From Spaceweather.com here |
STORM WARNING (UPDATED): Among space weather forecasters, confidence is building that Earth's magnetic field will receive a double-blow from a pair of CMEs on Sept. 12th. The two storm clouds were propelled in our direction by explosions in the magnetic canopy of sunspot AR2158 on Sept. 9th and 10th, respectively. Strong geomagnetic storms are possible on Sept. 12th and 13th as a result of the consecutive impacts. Sky watchers, even those at mid-latitudes, should be alert for auroras in the nights ahead.
UPDATE 1: I have posted a number of relevant items over the past few years on solar storm activity:
- General background about space weather, CME's and solar flare
- One of my most popular posts, a 2010 one titled "Solar activity (and Newt Gingrich)"
- An X5-class solar flare in March, 2012
- In January 2012, the biggest flare since 2005 and here.
- An aurora viewed as far south as the midwest
- And, another flare/CME on February 15, 2011___________________
This sunspot region has been active for a few months. On September 1 it was the source of a flare, but on the backside of the sun. However, this region is now directly facing the earth. Solar scientists are awaiting data, but they think that it's likely that a Coronal Mass Ejection (CME) of particles will follow. Information is updated regularly at NOAA's Space Weather Prediction Center here.
Why should we care? A CME has the potential to disrupt electronics that we depend on, whether in space for communications or on earth in health care facilities, computer centers, or communications facilities. A CME can also pose biological risk to astronauts and to passengers and crew in high-altitudes--especially if they are flying cross-polar routes where the particles preferentially come into the earth along magnetic field lines.
According to Mike Wall, a senior writer at Space.com, the sun "unleashed an X-class solar flare--the most powerful type" today, and it also fired off another intense flare yesterday. Fortunately, NASA in these times of diminishing funding, still has the Solar Dynamics Observatory spacecraft which recorded the event. The flare was an X1.6 storm, and space.com says that it "poses no danger to anyone on Earth or the astronauts living aboard the International Space Station." However, radio communications on earth, the side facing the sun could experience radio communications lasting 'more than an hour.' However, if the eruption is accompanied by a CME, in 2-3 days, there might be significant geomagnetic storms that can disrupt GPS signals, power grids, and communications.
We are near the peak phase of the Sun's 11-year cycle (Solar Cycle 24), but this phase is the weakest in about 100 years....and that's a whole other discussion!
Monday, September 8, 2014
Meteorite impact in Nicargua: brief report
The crater from the meteorite impact From this reference |
http://www.cnn.com/2014/09/08/tech/innovation/nicaragua-meteorite/index.html?hpt=hp_t2
Monday, September 1, 2014
A fissure near Bardarbunga volcano, Iceland, has erupted
Location of the fissure eruption at Bardarbunga from www.bbc.com here |

Saturday, August 30, 2014
The mysterious "sailing stones" of Death Valley
Credits as above. Picture grabbed from ScienceDaily.com. |
Stationary rocks (blue arrows) and rock moving from left to right (red arrow) |
The team used quarried rocks, one shown here with its GPS unit |
Floating ice moves around the playa under the influence of winds. When it encounters rocks, it may pile up on the upstream side, increasing the effective cross-sectional area of the rocks to both upstream ice and water and thus facilitating movement. On the other hand, sometimes the ice fragments upon encountering a rock. Norris and Norris suspect that this phenomenon might explain the Sharp and Carey observation of the corral behavior: the rock that didn't move out of the corral was just downstream of a stake that may have shattered the ice. Stones with low profiles might be submerged beneath the ice, some rocks may be too big for the available forces under some wind conditions, and others may not totally or partially encounter ice.
But, the researchers concluded, the mystery may not be completely solved: they didn't get to see the really big ones move.
The authors also point out that the sliding rocks are not unique to Racetrack Playa or even the U.S. Ice-driven rock trails are observed on the bottom of Great Slave Lake in northern Canada and on the shores of the Baltic Sea. The mechanism may apply to rock trails on dry lake surfaces in Spain and South Africa where the lakes are at high elevation and exposed to cold winters.
*Robert P. Sharp and Dwight L. Carey, Sliding stones, Racetrack Playa, California, GSA Bulletin, 87(12), 1704-1717.
**Richard D. Norris, James M. Norris, Ralph D. Lorenz, Jib Ray, Brian Jackson, Sliding rocks on Racetrack Playa, Death Valley National Park: First observation of rocks in motion. PloS ONE, 2014; 9(8) e105948 DOI:10.1371/journal.pone.0105948 link to article is here
Sunday, August 24, 2014
South Napa Earthquake today, M 6.0-6.1--geologic context
Building destroyed in Napa. Photo by Justin Sullivan, Getty Images as published on www.sfgate.com here |
and
Headlines this morning announced that a M6.0 (or 6.1, conflicting reports) earthquake at 3:20 a.m. awoke people around the area of Napa, California, north of San Francisco. Dozens of people are injured, four homes in a mobile park burned, and damage to buildings in downtown Napa appears extensive. The quake is the largest in the Bay Area since the 1989 Loma Prieta earthquake.
Here's a bit of context that I found in an on-line technical report authored by John R. Wesling and Kathryn L. Hanson, 2008 (reference at the end of this post). Here is also a link to the USGS earthquake event page.
Map of the five sections of the fault defined by Wesling and Hanson (Figure 3 from the cited report) |
Wesling and Hanson divided the fault into five reaches based on geomorphic expression, terrain traversed, and availability and quality of data. These branches are: St. Helena-Dry Creek; Yountville-North Napa; North Napa-Napa River; Napa River-American Canyon; and American Canyon-Carquinez Strait. The USGS is reporting that the earthquake struck 3 miles northwest of American Canyon, and placed the epicenter between 6 miles southwest of Napa, toward Vallejo (see adjacent map). According to the map above, this would place the epicenter on the Napa-River-American Canyon fault toward the northern end or, possibly, the southern end of the North Napa-Napa River branch, depending on where the reference point within Napa city is located.
No historical earthquakes larger than M6.0 have been associated with the West Napa fault, although the M5.0 Mount Veeder earthquake ("Yountville earthquake") in 2000 may have been linked to it. This earlier earthquake was centered about 5 km west of the West Napa fault, and caused considerable damage in Napa.
Reference: "Mapping of the West Napa Fault Zone for Input into the Northern California Quaternary Fault Database," by John R. Wesling and Kathryn L. Hanson, 2008.
Wednesday, August 20, 2014
Bardarbunga volcano, Iceland, rumbling!
UPDATE: August 23, 2014
UPDATE: UPDATE: August 23, 2014. Here is a link to the Icelandic Met Office Bardarbunga information. New information is constantly added at the top of the article. At 14:10 (Icelandic time), a small eruption of lava was detected under the Dyngjujokull glacier (east of Bardarbunga). Data from radar and web-cams (see this link, for example), have shown no signs of surface activity breaking through the 150-400 meter thick ice. However, the aviation code has been changed from orange to red, though no Icelandic airports have yet been closed. The Icelandic Met office estimates that it could be up to 20 hours before lava breaks through the ice, if it even does. The eruption could remain subglacial. Earthquake activity has continued since August 16. Flooding remains a possibility, with the bridge shown in the picture potentially at risk on the circum-Iceland road.
Earlier in the day, scientists reported that seismic activity indicated that a dyke was propagation as much as 5 miles to the north. On August 21, the dyke was reported to be 25 km long at a depth of 5-10 km. GPS data show that magma is moving.
ORIGINAL POST:
Earlier in the day, scientists reported that seismic activity indicated that a dyke was propagation as much as 5 miles to the north. On August 21, the dyke was reported to be 25 km long at a depth of 5-10 km. GPS data show that magma is moving.
Headlines are starting to appear about seismic activity under Bardarbunga volcano, which lies under Vatnajokull in Iceland, but with frustratingly little information as they hark back on the sensationalism of airplane flights cancelled when Eyjafjallajokull erupted a few years ago. More than 300 people in the region have been evacuated as a precaution. Flooding is a possibility.
Rather than paraphrasing, here are extracts from the Smithsonian volcano report:
13 August-19 August 2014
During 13-19 August the Icelandic Met Office reported increased seismic activity at Bárdarbunga volcano. On 16 August more than 200 earthquakes were reported under the NW Vatnajökull ice cap, and GPS stations have shown an increasing signal upward and away from the volcano since early June 2014. On 16 August the Aviation Color code was increased to Yellow. On 18 August the Icelandic Met Office reported an earthquake swarm to the E and another to the N of Bárdarbunga. A M4 earthquake was recorded that was the strongest in the region since 1996. By 18 August there had been 2,600 earthquakes detected at the volcano; earthquake locations from N and E swarms had been migrating NE, but in the evening activity of the N swarm had decreased significantly. That same day the Aviation Color code was raised to Orange.
The large central volcano of Bárdarbunga lies beneath the NW part of the Vatnajökull icecap, NW of GrÃmsvötn volcano, and contains a subglacial 700-m-deep caldera. Related fissure systems include the Veidivötn and Trollagigar fissures, which extend about 100 km SW to near Torfajökull volcano and 50 km NE to near Askja volcano, respectively. Voluminous fissure eruptions, including one at Thjorsarhraun, which produced the largest known Holocene lava flow on Earth with a volume of more than 21 cu km, have occurred throughout the Holocene into historical time from the Veidivötn fissure system. The last major eruption of Veidivötn, in 1477, also produced a large tephra deposit. The subglacial Loki-Fögrufjöll volcanic system located SW of Bárdarbunga volcano is also part of the Bárdarbunga volcanic system and contains two subglacial ridges extending from the largely subglacial Hamarinn central volcano; the Loki ridge trends to the NE and the Fögrufjöll ridge to the SW. Jökulhlaups (glacier-outburst floods) from eruptions at Bárdarbunga potentially affect drainages in all directions.
The Veidivötn fissure system, which extends 100 km SW from Bárdarbunga volcano, has been the source of major eruptions during the Holocene. A large, dominantly explosive eruption at about 870 AD from the Vatnaöldur crater row, which extends diagonally across the center of the photo, deposited tephra over much of southern Iceland. The Vatnaöldur eruption originated from a 42-km-long fissure and produced 3.3 cu km of tephra at the time of the settlement of Iceland, forming the the Landnam (Settlement) tephra layer.
The subglacial Loki-Fögrufjöll volcanic system...glacial ridges extending from the largely subglacial Hamarinn central volcano; the Loki ridge trends to the NE and the Fögrufjöll ridge, seen here, extends to the SW.
__________________________________________ |
Chaotic ice in Vatnajokull over Bardarbunga Image from the Smithsonian site here |
Earlier in the day, scientists reported that seismic activity indicated that a dyke was propagation as much as 5 miles to the north. On August 21, the dyke was reported to be 25 km long at a depth of 5-10 km. GPS data show that magma is moving.
ORIGINAL POST:
Earlier in the day, scientists reported that seismic activity indicated that a dyke was propagation as much as 5 miles to the north. On August 21, the dyke was reported to be 25 km long at a depth of 5-10 km. GPS data show that magma is moving.
Headlines are starting to appear about seismic activity under Bardarbunga volcano, which lies under Vatnajokull in Iceland, but with frustratingly little information as they hark back on the sensationalism of airplane flights cancelled when Eyjafjallajokull erupted a few years ago. More than 300 people in the region have been evacuated as a precaution. Flooding is a possibility.
Rather than paraphrasing, here are extracts from the Smithsonian volcano report:
13 August-19 August 2014
During 13-19 August the Icelandic Met Office reported increased seismic activity at Bárdarbunga volcano. On 16 August more than 200 earthquakes were reported under the NW Vatnajökull ice cap, and GPS stations have shown an increasing signal upward and away from the volcano since early June 2014. On 16 August the Aviation Color code was increased to Yellow. On 18 August the Icelandic Met Office reported an earthquake swarm to the E and another to the N of Bárdarbunga. A M4 earthquake was recorded that was the strongest in the region since 1996. By 18 August there had been 2,600 earthquakes detected at the volcano; earthquake locations from N and E swarms had been migrating NE, but in the evening activity of the N swarm had decreased significantly. That same day the Aviation Color code was raised to Orange.
Credit: Reuters, as published in bbc.com here |
The large central volcano of Bárdarbunga lies beneath the NW part of the Vatnajökull icecap, NW of GrÃmsvötn volcano, and contains a subglacial 700-m-deep caldera. Related fissure systems include the Veidivötn and Trollagigar fissures, which extend about 100 km SW to near Torfajökull volcano and 50 km NE to near Askja volcano, respectively. Voluminous fissure eruptions, including one at Thjorsarhraun, which produced the largest known Holocene lava flow on Earth with a volume of more than 21 cu km, have occurred throughout the Holocene into historical time from the Veidivötn fissure system. The last major eruption of Veidivötn, in 1477, also produced a large tephra deposit. The subglacial Loki-Fögrufjöll volcanic system located SW of Bárdarbunga volcano is also part of the Bárdarbunga volcanic system and contains two subglacial ridges extending from the largely subglacial Hamarinn central volcano; the Loki ridge trends to the NE and the Fögrufjöll ridge to the SW. Jökulhlaups (glacier-outburst floods) from eruptions at Bárdarbunga potentially affect drainages in all directions.
The Veidivötn fissure system, which extends 100 km SW from Bárdarbunga volcano, has been the source of major eruptions during the Holocene. A large, dominantly explosive eruption at about 870 AD from the Vatnaöldur crater row, which extends diagonally across the center of the photo, deposited tephra over much of southern Iceland. The Vatnaöldur eruption originated from a 42-km-long fissure and produced 3.3 cu km of tephra at the time of the settlement of Iceland, forming the the Landnam (Settlement) tephra layer.
The subglacial Loki-Fögrufjöll volcanic system...glacial ridges extending from the largely subglacial Hamarinn central volcano; the Loki ridge trends to the NE and the Fögrufjöll ridge, seen here, extends to the SW.
Wednesday, August 13, 2014
Weather extremes, atmospheric rivers and Japanese fire bombs
A shot-down Japanese fire balloon reinflated by the US File uploaded by Bkwillwm to Wikipedia, public domain |
In a new study by Dim Coumou and a team from Potsdam Institute for Climate Impact Research published August 11 in the Proceedings of the U.S. National Academy of Sciences (ref. below), Coumou points out that the large number of very high-impact extreme weather events over the past decades has seemed out of proportion to the rate of warming of the atmosphere caused by increased CO2. The authors rely on, and quote, an earlier paper in PNAS by Petoukhov, et al. (of the same institute) reporting the same thing: the frequency of these extreme events over the past decade is such that it is unlikely to be just a "stochastic mechanism of extremes."
And, here's where the Japanese discovery of the jet stream becomes relevant, because it's in the jet stream that the changing flow patterns are driving the weather extremes.
From the cited PNAS article. Shows the increase in so-called "boreal summer weather extremes." |
Now back to the research of Coumou and his team: According to the theory advanced in the article (based on analysis of meteorological conditions from 1979 to 2012), there are resonances in the atmosphere that trap the Rossby waves into certain configurations for long periods of time. Thus, a heat wave that would not be dangerous if it were a few days long, becomes extreme when its duration increases. (The paper is limited to analysis of the Northern Hemisphere.)
The speed at which a wave travels along the jet stream (the "phase speed") is, in one approximation, directly proportional to the mean zonal wind speed. To first order, synoptic waves with a wave number (k) equal to 6-8 travel at this speed. The zonal mean wind speed changes with season, being less in the summer. Because the zonal mean wind speed is lower in the summertime, the phase speed is also lower because of this direct proportionality. In fact, in the "boreal summer"--July, August--the phase speed can be close to zero (the waves are quasi-stationary, especially for wave number 6) or even negative (that is, the waves would travel to the west instead of the east). This weakening of the zonal wind speed and, hence, the wave speed is one mechanism explored. Free-traveling waves are simply slowed down or stopped. If the waves are stationary, then the troughs and ridges of the Rossby waves are stationary, setting in the northerly or southerly flow of air for long periods.
The second mechanism is the amplification of quasi-stationary waves by resonance between free and forced waves in the midlatitudes. Looking at the Petoukhov et al paper, the quasi resonance hypothesis is as follows. (1) Generally, the large-scale atmospheric circulation at mid latitudes is characterized by traveling Rossby waves with zonal wave numbers (k) equal to or greater than 6 propagating in the longitudinal direction at a phase speed of c~6-12 m/s as discussed in the paragraph above. (2) The circulation is also characterized by quasi stationary planetary-scale Rossby waves with c~0, frequency w~0, and various zonal wave numbers m that develop in response to orographic obstacles or weather sources and sinks, that is, to "conditions in the atmosphere that differ from place to place on the earth. Their hypothesis is that during the extreme summer events, persistent wave structures with high amplitudes evolved and made an unusually large contributions that the usually weak midlatitude response to the thermal and orographic sinks was strongly magnified at wave numbers 6,7 and 8.
They assert that the apparent cluster of resonance events observed in their data set (see their figure reproduced above) is due to an increased wave 7 and 8 resonances, and that furthermore, these resonances high in the atmosphere are coupled to persistent weather patterns at the surface, and thus the extreme weather events. The changes observed are statistically significant at the 95% confidence level.
The theory and data (from 1979-2012) suggest that because of warming in the Arctic, temperature differences between the Arctic and tropics are decreasing. Temperature differences drive the atmospheric circulation patterns, and changes in these differences (the temperature "gradients") are causing the atmospheric circulation patterns to change. Although much more detailed work and analyses needs to be done, their tentative projection (Figure 7) of conditions a century away shows t"similarities with the recently observed anomalies). According to RCP8.5 climate model (one in which we don't curb our CI2 emissions very much), the July-August thermal gradients will increase northward of 50N and decrease southward of 50N, leading to strengthening of the sub polar jet and weakening of the subtropical jet.
**I have used the report in ScienceDaily.com for parts of this post: http://www.sciencedaily.com/releases/2014/08/140811170106.htm
The abstract for the Coumou PNAS article is here and the full text is here.
The PNAS Petoukhov et al. article referenced is here.
Wednesday, August 6, 2014
Methane outbursts due to melting permafrost in Siberia: the Yamal crater
Image from the Washington Post here |
Several months ago, a photo of a crater discovered by a helicopter crew went viral. It is located in the Yamal Peninsula in Siberia, a desolate spit of land. The crater was variously reported to be 100- 200 feet in diameter. In the July 31 issue of Nature, highlighted in the Washington Post article referenced in the adjacent figure caption, the discovery of two nearby craters is reported in the Washington Post article. The article contains an excellent video taken from a helicopter showing the crater walls actively crumbling. A camera has been lowered to 50 m, and it showed a pool of water at a depth of 70 meters, so the crater extends below 70 m.
Image from Washington Post here |
Russian researcher Andrei Plekhanov led an expedition to the crater. He found that near the bottom of the crater (at approximately 50 m depth) air contained concentrations of methane up to 9.6%. That is to be compared to the normal concentration of methane in air--0.000179%. They believe that the abnormally hot summers in Yamai in 2012 and 2013 caused permafrost to thaw. Under the permafrost, usually at depths of 100 meters, methane clathrates are stable. Over the past 20 years, permafrost at a depth of 20 meters has warmed by about 2 C according to the article, quoting Hans-Wolfgang Hubberten of the Alfred Wegener Institute in Potsdam, Germany. Hubberten speculates that a thick layer of ice overlying the clathrates allowed gas pressure to increase until it was great enough to blow out in an explosive burst, forming the crater with rubbly ejecta strewn around it.
The development of more craters could pose a danger to villages of local reindeer herders, and the craters are only 30 km from a large gas field, the Bovanenkovskoye gas field. A blowout in the gas field cold be very dangerous.
Saturday, August 2, 2014
August 2 Major Landslide in Nepal blocks only route out to the North
Dave Petley's landslide blog will be providing excellent coverage. It is the peak of the monsoon season and so the impounded lake behind the landslide is likely growing fast and, Dave believes, may already be overtopping the dam. It also appears that the dam is in fine-grained materials and so the likelyhood of a breach is high. The valley downstream is heavily populated (evacuation has apparently already begun) and the main road from Nepal into China is blocked. The highway, however, does provide a route to bring in heavy machinery and crews to work on excavating a channel through the slide.
Thursday, July 31, 2014
Los Angeles geyser on Sunset Boulevard!
Back in the 1970's I used to run on the UCLA track near Sunset Boulevard. Two days ago, a 93-year-old water pipe and a 58-year-old pipe broke under Sunset Boulevard near the track, sending a pulsating geyser of water high into the air. You can view a video of it here (the video symbol in the center of the photo doesn't work because it's just a frame grabbed from the CNN video).
The track was flooded, as well as newly rennovated ($136 million)Pauley Pavilion, the home of UCLA basketball named in honor of the famous coach of winning teams back in the 1970's. At its peak, the broken pipes were sending 35,000 gallons of water per minute onto the streets, with estimates of 20 million gallons released before the flood was brought under control. Maybe the tartan track will survive, the basketball court is questionable. Firefighters had to rescue some people trapped in a parking structure
If you watch the video, you'll see that the jet is strongly pulsating. This is likely due to an effect known as a "water hammer." The pipeline was a high pressure line, and these lines are subject to very destructive forces due to the water hammer effect (sometimes called a hydraulic shock). These are pressure surges that arise when the water changes direction or momentum. In the news, you'll see reports that the pipeline had to be shut down gradually--that's because they had to minimize the potential for water hammers. If a pipe is shut off suddenly at the downstream end (where the vent is on Sunset Boulevard), the mass of water upstream is still moving and therefore can build up high pressure. Such shocks can cause further breakage in the pipelines. (This is common in noisy old water/steam heaters in buildings.)
I found an interesting set of numbers on Wiki about this effect: "In hydroelectric generating stations, the water travelling along the tunnel or pipeline may be prevented from entering a turbine by closing a valve. However, if, for example, there is 14 km of tunnel of 7.7 m diameter, full of water travelling at 3.75 m/s,[3] that represents approximately 8000 Megajoules of kinetic energy that must be arrested. This arresting is frequently achieved by a surge shaft[4] open at the top, into which the water flows; as the water rises up the shaft, its kinetic energy is converted into potential energy, which decelerates the water in the tunnel."
See the Wiki article for more on water hammers.
The track was flooded, as well as newly rennovated ($136 million)Pauley Pavilion, the home of UCLA basketball named in honor of the famous coach of winning teams back in the 1970's. At its peak, the broken pipes were sending 35,000 gallons of water per minute onto the streets, with estimates of 20 million gallons released before the flood was brought under control. Maybe the tartan track will survive, the basketball court is questionable. Firefighters had to rescue some people trapped in a parking structure
Flooded track and athletic field at UCLA |
If you watch the video, you'll see that the jet is strongly pulsating. This is likely due to an effect known as a "water hammer." The pipeline was a high pressure line, and these lines are subject to very destructive forces due to the water hammer effect (sometimes called a hydraulic shock). These are pressure surges that arise when the water changes direction or momentum. In the news, you'll see reports that the pipeline had to be shut down gradually--that's because they had to minimize the potential for water hammers. If a pipe is shut off suddenly at the downstream end (where the vent is on Sunset Boulevard), the mass of water upstream is still moving and therefore can build up high pressure. Such shocks can cause further breakage in the pipelines. (This is common in noisy old water/steam heaters in buildings.)
Photo of Pauley Pavillion basketball court by Jason McIntyre |
See the Wiki article for more on water hammers.
Wednesday, July 9, 2014
Gorgeous Air New Zealand plane! (And, how much can Dreamliner wings flex?)
The new Air New Zealand Dreamliner; photo from CNN.com here |
"The amount of flex is really a product of the material. The wing requires a specified ultimate strength; with metal, that translates into a given amount of flex. This can be varied within limits, but it is really the material, its stiffness to yield point ratio, and its fatigue properties, that control how much flex you are going to end up with. CFRP is a very different material, and has much less stiffness for the same yield point, and has essentially no fatigue problems. This is beneficial in that it provides a smoother ride in turbulence; the wing acting essentially like a giant leaf spring. There is some lift lost due to the nature of the curvature, though. However, this is relatively small."
Monday, July 7, 2014
Super-typhoon Neoguri ("racoon") approaches Okinawa
Super-typhoon Neoguri, first super-typhoon of 2014 imaged on July 6 (?) by NOAA/EPA |
Three inches of rain PER HOUR??? I wonder for how many hours!! Waves up to 14 meters (45')? I have friends on Okinawa and wish them well (and also asked them to send a first hand report!) The storm is expected to work its way up to mainland Japan by Wednesday. The highest danger is for Miyako-jima, in the center of the archipelago.
As I write this (Monday a.m. PDT) gusts of up to 270 km/hour (160 miles per hour) are expected, and the Japanese national weather agency is saying that this may be the worst storm in decades. This is the first storm of hurricane season there, and it is apparently hitting rather early in the season. The US evacuated some of its plane from Okinawa in advance of the storm.
Projected path and conditions, from the Japan Meteorological Agency |
In summary, here, in the last figure, is the Accuweather forecast for the west Pacific for 2014.
Friday, June 20, 2014
Is an El Nino in the offing?
The record of La Nina's and weak El Ninos that have occurred since the last powerful El Nino in 1997-1998. From the Nikkei Asian Review cited in the text. |
What has caused this speculation? Normally the trade winds blow from east to west, but in January and February there were two strong westerly bursts, followed by two "slightly less powerful" ones in March and April. If such bursts continue and develop into a reversal of the trade winds, an El Nino will occur. Warm surface waters of the Pacific will be pushed easterly toward the west coast of South America.
Although highly speculative at present, a switch back to El Nino conditions may have significance in the bigger picture. La Nina conditions have permitted storage of heat in the deep waters of the Pacific. Storage of heat in the ocean takes it away from the atmosphere, keeping global warming in check. The haitus in global warming in recent years may be due to this string of La Nina events. A switch back to El Nino conditions, particularly if they last a decade or more as is common, could result in a resumption of global warming conditions. Here's a link to a Slate article on the possibility, and here's Cliff Mass's comments about it, as well as the quality of forecasts made in April, the time of these two articles.
Typical El Nino weather conditions. From here. |
The Asian Review article also notes that because of budget cutbacks, 24 of NOAA's 55 ocean buoys in the tropical Pacific are unable to operate and send data needed for monitoring the situation.
Monday, May 26, 2014
Massive mudslide in Colorado on Sunday, Memorial Day weekend
The Sunday, May 24, Mesa County Mudslide. Dimensions are uncertain, but at least 0.5 mile wide, 2-3 miles long, and 250 feet deep. Photo by Aaron Ontiveroz, Denver Post as published here. |
Heavy rain again (after Oso and Afghanistan) appears to have triggered a massive mudslide, this time in the Grand Mesa country of Colorado. The location is 11 miles southeast of Collbran, about 40 miles east of Grand Junction. The area is remote, cell coverage is sparce to nonexistent, and news is just starting to break of this event. More than 3/4" of rain hit the area on Sunday. Three men, locals who had gone into the area to investigate the possibility of a smaller slide when they noticed problems with their irrigation water, are missing.
Update May 26: Weather.com meteorologist Jon Erdman said that Grand Junction picked up 0.42 inches of rain on Sunday, and that higher totals atop Grand Mesa above the slide were likely Heavy rain is expected toward the end of the week and into the weekend, making the slide area still very dangerous.
Location of Collbran ("A") relative to Grand Junction |
Another photo of the mudslide taken by Aaron Ontiveroz as found here. |
The area where the landslide climbed a hill is at the upper right of this image. It is at a sharp bend in the path of the flow. Photo also by Aaron Ontiveroz, Denver Post. |
Update 5/26: Geologist Jonathan White, with the Colorado Geological Survey, said that another slide seems inevitable because of the buildup of water in a depression created by the big slide. The depression that he's referring to may be (???) at the top of the slide in the lower photo. Water has been flowing into the depression already, but White says that it's impossible to tell when the next slide could occur--perhaps even years from now when people have forgotten the danger. The terrain is too unstable for any work to drain the water, and Jonathan Godt, a geologist with the USGS says that "practical engineering measures for things of this size are pretty limited."
Update, May 28: The last photo in this set shows the mobility of the flow as it climbed up and over the ridge in the upper right where it took a sharp right turn in the flow path. From a topo map of the area, it looks like the elevation of the headwall at its crest is roughly 9700 feet, and that the elevation where the slide began the right-angled turn is about 8000 feet. This drop of 1700 feet elevation occurred over about 1.5 miles. It looks like the topped a ridge that is a couple of hundred feet higher than the valley bottom (where it spilled over the ridge on the right side as viewed in the photo, left side when viewed from the flow direction). Since the slide was reported to be several hundred feet thick, it's not clear how much of this spill-over was due to the energy of the flow versus the thickness of it as it approached the ridge. Note the erosion line of the trees in the extreme upper right of the photo and how it appears to be close to the elevation of the top of the overtopped ridge. This suggests to me that the overtopping had a significant contribution just due to the huge thickness of the flow.
There is also a very unusual change in texture between the material that did not go up the hill (streamwise right) and the material on the proximal side of the hill (rough vs. smooth?), and I'm wondering if bigger particles in the flow got left behind as the more fluid finer-grained material climbed the hill? Did the flow climb the hill on its left side (toward the top of the photo) and then fall back toward the valley on its right side (the smooth area on the right side of the ridge)? Is it possible that the "slide" changed to a muddy flow at this point--certainly there is a change in the texture of the slide downstream from this area, as pointed out today by Dave Petley on his AGU landslide blog. Field observations will be needed to clarify many questions.
After making the first turn to the right, the material then turned to the left, spread out around and over a region of ridges (emanating from the hill on the streamwise right side of the flow in the middle of the photo), and eventually exited from the main channel, narrowly missing a developed site of some sort (natural gas, fracking facility??). I'm not sure what this is, and the WWW is full of speculation. The elevation of the toe of the slide is about 7300 feet, making the total drop of the order of 2400'.
Friday, May 23, 2014
Camelopardalid meteor shower
In the lower right half of the image you can see the shape of a giraffe and the location of the Camelopardalids meteor shower tonight. Courtesy Science@NASA. |
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Plot of the Earth's path through the meteor shower by Jeremie Vaubaillon. |
Comet 209P/LINEAR was discovered on Feb. 3, 2004, by the Lincoln Near-Earth Asteroid Research (LINEAR) research project. It orbits around the sun with a period of roughly 5 years, with an aphelion out near Jupiter's orbit. As a result, calculations show that its orbit has been perturbed by the gravitational pull of Jupiter over the past few centuries, at least as far back as 1798. Most particles in the shower are smaller than a grain of sand and burn up high in the atmosphere.
Scientists are being cautious, predicting a few hundred meteors per hour to be on the safe side, but almost all of them express hope for the storm-level of 1000 per hour. Comet 209P/LINEAR is a small comet, and has in recent passes near the earth, a fairly low dust production. Observers in the United States and southern Canada are in the best position to see the shower. The moon is a waning crescent, just four days from the dark new phase and will not be a hindrance.
Fred Whipple first developed the idea that comets were "dirty snowballs" orbiting the sun.The meteoroids are formed when a comet passes by the sun and some of the ice (water, methane, ammonia or other volatiles) sublimates, releasing the small silicate particles bound in it. The meteoroids spread out around the comet, eventually, after many passes by the sun, filling in the entire orbit.
Here is a link to Mikhail Maslov's website on the 2014 meteor shower, and here is a post by Robert Lunsford.
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