NatHazMap.com News Archive
February 21, 2011
On February 19th an avalanche killed 3 skiers near the Stevens Pass Ski Area in the Cascade Mountains of Washington State. The skiers killed were part of a larger party of backcountry skiers in the Tunnel Creek/Cowboy Mountain area which is accessed from the ski resort. A total of 5 were caught, 2 were partially buried and rescued by party members, 3 were killed in the slide. All skiers were highly experienced and equipped for backcountry travel. The Northwest Weather and Avalanche Center (NWAC) had rated avalanche hazard as "high" on the day of the accident. A detailed account of the accident is available at the Seattle Times website.
On the same day a snowboarder was killed in a separate accident on Snoqualmie Pass. A total of 7 have been killed in avalanche accidents in just the past week. In the U.S. Mountain West this season an especially thin and weak snowpack have combined with an increased number of backcountry users to produce an increased number of accidents with many tragic results. So far this year in the USA a total of 18 have been killed by avalanches. The average is 25 total per year. With many more months of snow recreation still to come the number of avalanche fatalities is sadly likely to be above average. A summary and statisitics of the current seasons avalanche accident can be found on Avalanche.org accidents page, record-keeping courtesy of the CAIC. Additional information and resources on avalanche hazard mapping can be found on our Avalanche page.
Sources: CAIC, Avalanche.org, NWAC, Seattle Times
Tags: avalanche, weather
February 12, 2011
We've recently completed a restructuring of NatHazMap.com and have added many new features. Notice that the menu is now easier to navigate, and many pages now have live, real-time updating of natural hazard warnings, watches, and news. We hope you enjoy the new features and find this a more timely and relevant source for natural hazard mapping.
Much more changes are in store. Now that the update is in place we plan to add new content on a weekly basis, including news items and continuing the long-term effort of compiling natural hazard map resources for around the world. We've also added pages for interactive maps, full-sized free downloads of maps we've created, and sources for natural hazards related GIS data.
We apologize for being away for so long and not done many news updates or added much new content. Just been too busy! For the most part this site is a one-person effort and is done entirely on a volunteer basis with no compensation. Not only do updates take time away from our real-jobs, but we also web domain registration and hosting costs.
Soon we will be adding some limited advertising to hopefully cover part of operating costs. We will try to keep advertising relavant to the content on the site and also as discrete and unobtrusive as possible so as not to detract from the user experience. We will both be using ad services and eventually selling ad space directly to selected natural hazards mapping related companies. If your company may be interested please get in touch about advertising.
We hope you enjoy the recent updates and the ones we have in store for the future. For questions, comments, or suggestions, please contact us. We'd love to hear your feedback.
March 11, 2011
A large earthquake with a magnitude of 9.0 occurred on Friday, March 11th off the coast of Japan. The resultant tsunami killed thousands and caused widespread damage. This was a major event and was reported worldwide. Typically, news items featured a map which showed the location of the earthquake. It seems that the most common method used to depict the epicenter was a series of concentric circles radiating outward from the earthquake epicenter.
Numerous methods seem to be in use when drawing circles, and some maps seem to arbitrarily place circles with no regard to actual shaking or damage on the ground (see examples below). Whether intentional or not, the extent and thickness of the circles used in these maps imply a certain geographic area in which the earthquake was felt or damage resulted, and the intensity of of shaking in these areas. For better or worse, symbology influences perception, and when choosing map symbols it is important to consider the effect of graphics on public perception of the disaster hazard event.
The development of a useful method of earthquake depiction using concentric circles could standardize the practice, and help achieve a uniform message of earthquake intensity as depicted in maps, regardless of the source. A numerical model could be used in interactive maps, or could be developed into a script that could be applied in mapping/GIS software when drawing an earthquake location map. For the purposes of this article, several methods were evaluated, and some preliminary general principles for earthquake depiction are proposed.
The image above shows four different examples. In example 1 (The Daily Mail), radiating concentric circles are used with line thickness decreasing with distance from the epicenter, presumably to represent decreasing intensity. The outermost circle however, stops just short of a specific report of damage. This is problematic because the circles imply an area of felt shaking. In example 2 (BBC), however, the circles cover a much wider area, probably somewhat close to the area that experienced major shaking. In example 3 (Relief Web), from a different earthquake, the lines are at specified distances, in this case 100 miles apart. This is useful, but with both the same distance and line thickness, the map does not visually convey the impression of decreasing intensity with distance. In example 4 (GeoMap.org), a simple "bulls-eye" symbol is used , similar to circle 22 in the ArcMap symbol selector. In this case magnitude is also labeled, but in the absence of the label, the use of small symbol would imply a small seismic event, especially when compared to the other maps.
For the purposes of this I wanted to find a method that could use both decreasing thickness and increased distance to help visually represent the earthquakes effects. Decreasing line thickness is relatively straightforward, and widely used, but the challenge was in determining what distance apart to place the circles, and at would distance to no longer show them. In the below examples used a series of circles created as buffers in specified distances. I chose to use 9 circles, or one to represent each order of magnitude, with the assumption that smaller earthquakes could employ less circles and cover a smaller area. I depict these circles over the USGS Did you feel it? Tell Us map which is based on user submitted reports of felt intensity.
For the above two maps I tried equal intervals of 50 and 100 km respectively. The first obviously does not cover enough area. The second does a better job but implies that the earthquake was not felt in the mainland, which submitted reports suggest otherwise. While decreasing line thickness could be employed to suggest intensity, increasing distances (similar to a ripple) could help as well so I tried to find a numerical method that could achieve a visual "ripple" effect.
Earthquake magnitudes increase exponentially, i.e a M9 quake is 10 times more powerful than a M8. So for the above example I tried placing circles at distances of 10, 100, and 1000km, obviously doesn't achieve desired visual effect and 9 circle would exceed the size of the planet, so moving on.....
Next I tried doubling, or increasing the distance by a factor of two. I tried starting distances of 2, 5 and 10 km.
Of the three maps above I think the second, with a 5km initial distance is the best. However the innermost circles are very close together and hard to see. However, with decreasing line thickness, it could work quite well. The only problem is that the actual distances themselves, at 5, 10, 20, 40, 80, 160, 320, 640, and 1280 km are not often used to describe distances, and convenient multiples of 50 or 100 would be more useful.
It is important to note that, while felt intensity increases exponentially with magnitude, with distance, felt intensity decreases in more linear, or slightly curved manner, as shown on the graph for this earthquake below (keep in mind the compressed horizontal scale on this graph enhances the curve).
So I tried a few maps where distance would increase slightly with each successive circle, in order to very roughly approximate such a curve. I tried several formulas and settled on one where the distance increases each time by the amount of the original distance. Here's a couple that worked okay.
Of the two above maps, I think the first one works the best. While the second does extend outward to areas of some felt reports, damage in those areas was nonexistent and it seems that actual area affected by the earthquake is better approximated by the first map. So think we're getting there, but again the distances are not very commonly used, and more multiples of 100, 200, and 500 would be nice if possible.
So for the next couple maps, I chose the distances at convenient, or useful intervals, but making sure that distance between each circle was either equal to, or greater than, that of the previous circles. I tried several combinations, and don't want to make this any longer, so the best result is shown below.
This map achieved the desired visual effect I was trying to achieve, and also had circles at fairly convenient distances of 5, 10, 25,50, 100, 250, 500, 800, and 1200 km. The main problem is at this scale the smaller circles are hard to see. However this would be less of a problem either on large maps or the more common, lower magnitude earthquakes which affect a smaller area. So I chose to use this series of circles, combined with Natural Earth background data to produce the map at the beginning of this article. I also decreased the line thickness from 3 pts down to 0.2 pts with distance from the epicenter.
Obviously this is quite preliminary. I will try this method on future events and refine it further. A more detailed study including numerous earthquake and incorporating multiple intensity vs. distance curves could produce a numerical model for drawing earthquake location concentric circles. This could be developed into a python or other script that used inputs of earthquake latitude, longitude, and magnitude to automatically draw buffers. Another script could be developed for use in either ArcGIS, MapPublisher, or Illustrator, to further symbolize the circles with line thickness, color intensity, and/or opacity decreasing with distance. For now a few more informal tests of this method and others on future events is in order.
The symbology used in an earthquake map can affect perception of the earthquakes actual impact. A combination of increasing spacing and decreasing line thickness can help visually approximate felt earthquake intensity and damage. Further testing is necessary in order to develop a numerical model for depicting earthquake intensity as a series of concentric circles. For now some general principles can help achieve the desired effect:
-use common distances when possible i.e. 50km, 100km, etc.
-use one circle per order of magnitude
-distance between circles should increase with distance from earthquake epicenter in a linear, or slightly curved fashion
-line thickness should decrease with distance from earthquake epicenter in a linear, or slightly curved fashion
-consult felt intensities maps and damage reports to ensure that the areal extent of circles shown and method used conveys the actual impact of the earthquake on the ground.
I would appreciate any comments on this. Thanks!
Sources: USGS, BBC, The Daily Mail, Relief Web, Geomap.org
Tags: earthquake, tsunami
March 11, 2011
A large earthquake with a magnitude of 8.9 occurred at 2:46 PM local time on Friday, March 11th off the coast of Japan. The earthquake also triggered a major tsunami which killed at least hundreds in Japan and resulted in damages around the Pacific Rim. Widespread damages have been reported. The situation is unfolding and it will be days, if not weeks, before more accurate estimates of casualties and damage are available.
The earthquake was the result of thrust-fault activity on or near the subduction zone interface plate boundary between the Pacific and North America plates. The March 11 earthquake was preceded by a several large foreshocks over the previous two days, beginning March 9th with an M 7.2 event approximately 40 km from the March 11 earthquake, and continuing with a further 3 earthquakes greater than M 6 on the same day.This is largest measured earthquake to affect Japan since record keeping began.
Following the earthquake, a major tsunami struck the coast of Northern Japan, with greatest damage occurring in the Sedai area. Dramatic news footage shows the incoming tsunami, with estimated heights between 4 and 10 m, overrunning buildings, vehicles, and boats, no doubt killing many of the occupants in the process. Widespread damage is evident and the country is in a state of emergency, with international assistance arriving to help. Rescue, recovery, and relief efforts are ongoing.
Widespread warnings were issued for low-lying areas around the Pacific Rim. Damages were reported in areas such as Hawaii and Northern California, USA, but damage at this time seems to be minimal in comparison to the situation in Japan. While Japan is especially prepared for seismic events of this magnitude, the tsunami was exceptionally large, with little time for low-lying areas to evacuate, and the results are indeed tragic. We wish the best to all those affected by this disaster.
Sources: USGS, New York Times
Tags: earthquake, tsunami
August 6, 2010
Flooding in Pakistan has now killed an estimate 1,600 people and affected over 12 million. Continued heavy rains associated with the monsoon have resulted in extensive flooding along the Indus River System and its tributaries (see map below). An estimated 650,00 homes have been destroyed and 1.4 million acres of cropland have been inundated.
The Pakistan Meteorological Department (Pak-Met) has issued a flood warning for low-lying areas of the Sindh province, among others. In addition, heavy rains are forecast to continue, and are expected to worsen the situation. Pak-Met's website provides detailed flood hazard maps which show the areas under imminent threat. Authorities have evacuated over 500,000 people in 11 Sindh Districts.
The floods are by far the worst in Pakistan History. General Nadeem Ahmed of the Pakistan Disaster Mangement Authority stated that the floods will be the "biggest disaster in the history of Pakistan." The low-lying areas of Pakistan are prone to seasonal flooding due to the monsoon - see ReliefWeb's Pakistan Flood Risk Map, but an especially heavy monsoon season has produce unusually high rainfalls and the resultant record floods.
For continued updates on the situation use the Pak-Met website. For detailed maps of affected areas see Reuter's AlertNet Map Catalogue, or ReliefWeb's Pakistan Flood Maps page. To donate to the relief/assistance effort a good resource is the Pakistan Red Crescent Society.
Sources: BBC, Pak-Met, AlertNet, ReliefWeb
Tags: weather, flooding
July 22nd, 2010
On April 20th 2010 the BP-Operated Deepwater Horizon Oil Drilling Rig exploded, killing 11 workers and destroying the rig, which later sank. Oil began spilling into the Gulf of Mexico, and initial efforts to cap the well were unsuccessful. Drilling of relief wells began with an expected completion in mid-August. Since the explosion millions of gallons of oil have spilled into the Gulf, making this the largest environmental accident of its kind in US history. The estimated near-surface oil slick as of today is shown below.On July 15th the wellhead was successfully (so far) capped, and recently the drilling of the relief wells was announced to be ahead of schedule. A "static kill" procedure is planned to permanently seal the wellhead. However, a tropical depression in the Gulf of Mexico has halted some work and threatens a delay in the efforts to permanently stop the flow. If the tropical depression develops into a tropical storm or hurricane it could have a significant impact, both on the mitigation efforts and on the location of the oil itself.
A complete description of the events of this environmental disaster and its potential effects on human health and the Gulf Ecosystem is well beyond the scope of this article. Much has been written and is readily available. One thing that stands out vs. previous incidents is the increased use by responders, and availability to the public of GIS-based maps and interactive mapping applications. Some noteable examples are below.
Deepwater Horizon Response - the Official Site of the Deepwater Horizon Unified Command
NOAA OR&R - NOAA's National Ocean Service Office of Response and Restoration
Geoplatform.gov/gulfresponse - Interactive map of all things related to the spill developed by NOAA with the EPA, USCG and Dept. of the Interior
Gulf of Mexico Oil Spill Social Media Map - Courtesy ESRI
Gulf of Mexico Oil Spill Timeline Map - Courtesy ESRI
Gulf of Mexico Oil Spill Economic Impact Map - Courtesy ESRI
Gulf of Mexico Oil Spill resources - Additional information, data, maps and applications related to the spill compiled by ESRI
NTY's Tracking the Oils Spill Map - an excellent interactive/animated map by the New York Times tracking the oil spill and its landfalls.
Sources: USGS, NOAA, ESRI, New York Times
Tags: Environmental, Hurricane
April 17th, 2010
The Eyjafjoll, or Eyjafjallajokull, volcano in southern Iceland continued erupting, causing damage in southern Iceland and disrupting air travel through Europe. The volcano first began erupting on March 21st, prompting local evacuations and canceling some flights in and out of the country. The more recent, and larger, eruptions began on April 14th. Melting of its glaciers caused mudflows, debris flows, and flooding, at its base. Meanwhile a large column of ash from the eruption spread across Europe, causing widespread flight cancellations.
Eyjafjoll, a stratovolcano, is located in southern Iceland (see map), and last erupted between 1821 and 1823. Eyjafjoll is largely covered in ice, and was was inflating with a period of increased seismicity prior to the eruption. This eruption initially began on March 31st, while the more significant phase began April 14th. At this point it is unknown just how long the current eruptive phase will continue. An extended eruption of this magnitude could have global climatic effects.
Scientist will continue to monitor the situation at the volcano. For more information on Eyjafjoll's eruptive history, we recommend visiting the Global Volcanism Program website. For recent news, warnings, and weather conditions, visit the Iceland Meteorologic Office website.
Sources: USGS, BBC, Smithsonian Global Volcanism Program, Iceland Meteorologic Office
April 16th, 2010
An earthquake with a magnitude of 6.9 occurred in China on April 13th, 2010. The earthquake was located in the Qinghai province approximately 1190 miles southwest of Beijing. The earthquake was the strongest to strike the region since the magnitude 7.9 earthquake in May of 2008. So far it is estimated that at least 1,144 people were killed, 417 are missing and 11,744 are injured as result of this event.The earthquake occurred several hundred kilometers north of the convergent Indian/Eurasian plate boundary, where the Indian continent in moving northward at a rate of 4.6 cm/year, driving the uplift of the Himalayan Range. Several large historic earthquakes have previously occurred in this region, including the Sichuan province quake of 2008 which killed an estimated 70,000 people.
Aid is arriving to the remote areas of the region but rescue workers say there is a critical need for further supplies. An estimated 15,000 houses were destroyed in Yushu county, leaving thousands homeless. Soldiers, rescue workers and Buddhist monks have been using pickaxes, shovels and their bare hands to search the rubble for survivors. The casualty toll will like increase as additional reports come in.
For more information and additional maps visit the USGS M6.9 China Earthquake page, or the list of China Earthquake Information resources. For seismic hazard maps and historical seismicity maps for greater Asia, refer the USGS list of Asia Earthquake maps.
Sources: USGS, BBC
April 5th, 2010
An earthquake with a magnitude of 7.2 occurred at approximately 3:40 PM (PDT) on April 4th. The earthquake was located approximately 40 miles south of the US-Mexico border. The earthquake was the strongest to strike the region in two decades and was felt by an estimated two million people. While no deaths or major injuries were reported in the United States, in Mexicali people people were killed and 230 were reported injured.
The earthquake occurred at a shallow depth along the principal plate boundary between the Pacific and North about 45 mm/yr movement of the Pacific Plate to the NW. The plate boundary consists of a series of NW-trending transform faults, distinct from, but parallel to, the San Andreas. The exact location/fault on which this recent earthquake occurred is unknown at this time. Earthquakes with a similar magnitude have previously occurred in this area,with strong quakes in 1892, 1915, 1934.
Since the earthquake, numerous smaller aftershocks have been measured, extending to the NW and SE along the fault system. Seismologists cautioned that strong aftershocks were likely, but that a larger quake, while still possible, was fairly unlikely. Visit our earthquake page for more resources and map of seismic hazard in the US, including California.
Sources: USGS, LA Times
March 22nd, 2010
The Eyjafjoll, or Eyjafjallajokull, volcano in southern Iceland began erupting on March 21st. Continued eruptions, combined with increased seismicity, have raised concerned that a larger eruption could be triggered on Katla, an adjacent larger volcano with a more violent recent eruptive history. Nearby towns have been evacuated and international flights in and out of Iceland have halted due to ash in the atmosphere. At this time there have been no reports of deaths, major injuries, or significant damage due to the eruption.
Eyjafjoll, a stratovolcano, is located immediately west of Katla (see map), and last erupted between 1821 and 1823. Eyjafjoll is largely covered in ice, and was was inflating with a period of increased seismicity prior to the eruption. Ash from the eruption has been reported in northern Europe. While this eruption has been relatively mild, and floods due to melting of its icecap are expected to be minimal, the concern is that an eruption on the nearby volcano Katla could be more dangerous.
Katla is located just west east of Eyjafjoll under the Myrdalsjokull icecap. The volcano is one of Iceland's most active volcanoes and is a frequent producer of damaging jokulhlaups, or glacial-outburst floods. Records indicate that Katla often erupts following eruptions at Eyjafjoll. An eruption at Katla is likely to be more explosive and produce more damaging floods. A major eruption could have global climatic effects.
Scientist will continue to monitor the situation at the two volcanoes. For more information on the volcanoes and their history, we recommend visiting the Global Volcanism Program website. For recent reports of earthquakes related to the volcanoes, and to monitor news, warnings, and weather conditions, visit the Iceland Meteorologic Office website.
Sources: USGS, BBC, Smithsonian Global Volcanism Program
Tags: volcano, earthquake
February 27th, 2010
A large earthquake with a magnitude of 8.8 occurred off the coast of Chile. Chile's capital, Santiago, experienced very strong shaking as a result. The earthquake also triggered a tsunami which killed hundreds in Chile and sounded alarms around the Pacific Rim. Current estimates include 0ver 700 killed and millions affected by both the earthquake and tsunami. Widespread damaged and collapsed buildings have been reported. It will be days, if not weeks, before more accurate estimates of casualties and damage are available. Rescue and recovery efforts are ongoing at this point. The earthquake was the result of thrust-fault activity at the boundary between the Nazca and South American Plate. Chile has experienced some of the largest instrumentally recorded earthquakes ever, with 13 events of magnitude 7.0 or greater since 1973. In 1960 the world's largest recorded earthquake, with a magnitude of 9.5, occurred just over 100 miles south of the epicenter of the recent quake.
Following the earthquake, tsunami warnings and watches were issued for low lying coastal areas in the Pacific Rim, including the Pacific Islands, New Zealand, Hawaii, western North America, and Japan. Beaches and coastal areas in Hawaii and the western US were evacuated, but run-up from the tsunami was minimal and damage, where present, turned out to be less than expected. This is in contrast to the Chilean fishing village of Concepcion, where hundreds were killed by the tsunami.
Even thought this earthquake was significantly more powerful than the recent Haiti event, damage and deaths as a result were significantly less. This is due to numerous factors. Firstly, this quake occurred much farther away from Santiago, the major population center of Chile. Secondly, Santiago is built on more consolidated materials than Port-a-Prince, and is prone to less shaking. And thirdly, with numerous large earthquakes in recent history, Santiago was much more prepared for the event. More strict building codes and earthquake-resistant construction methods, along with a more affluent society with the resources to support such practices, resulted in substantially less structural damage than in Haiti.While the death toll may rise and this is indeed a tragic event, in the light of the recent events in Haiti, it appears that Chile has fared quite well considering the magnitude and shaking intensity of this recent event. Continued research and mapping of earthquake-prone areas is necessary to educate the general populace on earthquake hazard, and promote earthquake-resistant construction practices to reduce risk in such areas.
Sources: USGS, BBC
Tags: earthquake, tsunami
February 13, 2010
Two deadly avalanches in the greater western Himalayan mountains have killed over 180 people. On February 8th a large natural avalanche at the Gulmarg Ski Area in the Indian controlled Kashmir Region killed 18 people. On February 10th another large natural avalanche killed an estimated171 people on Salang Pass, north of Kabul, Afghanistan.The avalanche on February 8th struck a group of Indian soldiers at a high altitude army training camp near the Base of the Gulmarg Ski Area in the Kashmir region.17 soldiers were killed and 17 others were critically injured. 53 were rescued. Prior to the avalanche, storm totals of 135cm of new snow were reported in Gulmarg village, with an estimated 3 meters of accumulation in the start zone areas. Snow in the deposition zone was up to 4 meters in depth and 100 year old trees were broken in half by the powder blast.
The avalanche originated from the Chooti Nali Bowl start zone, among others, and ran beyond historical limits into mature timber at the base of the slidepath. Gulmarg boasts the highest altitude gondola access in the world, and is known for its expert/extreme avalanche terrain, heavy snowfalls, and consistent powder skiing condition. More information and photos of the slide paths can be found at the Gulmarg Snow Safety website.
Another tragic avalanche accident occurred in Afghanistan just two days later. Numerous avalanches struck Salang Pass just north of Kabul, and were the result of heavy winds, wet snow, and rain-on-snow activity prior to the slide. The death toll has reached 171 people, and over 300o have been rescued. The toll will likely rise as recovery efforts continue. Currently rescue dogs and satellite remote-sensing imagery were being used to search for additional victims.
Salang Pass links the the capital city of Kabul to the northern city of Mazar-i-Sharif. Salang Pass crosses the Hindu Kush mountain range, a sub-range of the greater Himalayan Chain. At 12,700 ft/3,800m it is one the highest major passes in the world and is prone to frequent avalanche events. Last year, avalanches killed almost a dozen people on the pass. This accident, however may turn out to be one of the deadliest natural disasters to occur on Salang Pass, and possibly one of the worst natural disasters ever in the country.
Sources: AP, CNN, BBC, Gulmarg Snow Safety
Tags: avalanche, weather
February 3, 2010
On Tuesday, January 12th an earthquake with a magnitude of 7.0 rocked the island Nation of Haiti. The earthquake was associated with the Enriquillo-Plantain Garden fault system and was centered approximately 15 miles to the southwest of the Haitian Capital, Port-au-Prince. Significant historical earthquakes associated with the fault system also occurred in 1751, 1770, and 1890.
Current estimates include over 200,000 killed, at least as many injured, and in excess of 1 million displaced. Port-au-Prince was effectively destroyed with major government, buildings, including the Presidential Palace, damaged or destroyed. Reports of trapped people being recovered alive from collapsed buildings have occurred as late as two weeks from the quake. It will be weeks or months until accurate damage estimates are available and years until the nation can even begin to resemble its former self.
While similar death tolls have occurred in other countries due to seismic events, this one is somewhat unique as the entire country was effectively destroyed. With many of its buildings destroyed and officials killed, the government was incapacitated and the people of Haiti were left to rely on other nations for aid.
The outpouring of help from both foreign governments and their citizens in the wake of this tragedy is a testament to the inherent good nature of humankind. The recovery is only beginning however, and continued donations and volunteer work will be necessary for many years to come in order to help our neighbor rebuild and recover.
The nature of this earthquake, and earthquakes in general, is that it is not the natural disaster event itself that kills people, but rather the failure of human structures. This is in contrast to to many other types of hazards such as tsunamis, wildfires, landslides, floods, and avalanches where the forces of the natural hazard event itself directly result in loss of life.
Since the bulk of deaths as a result of earthquakes occur due to structure collapse or failure, it can be posited that loss of human life due to seismic events is largely preventable. In areas of increased seismic hazard, strict building standards are necessary to prevent structure collapse in the event of a quake. For a global map of seismic hazard, we recommend referring to the Global Seismic Hazard Assesment Program and contacting local authorities to determine appropriate construction methods. Developing nations such as Haiti are at increased risk as maps of seismic hazard are less available, and building standards are generally less strict and often poorly enforced.
We wish the best to the Haitian people and to all those affected by this tragedy. For mapping professionals involved in the Haitian recovery effort, the following website, courtesy of ESRI, has a list of map and data resources:
October 27, 2009
What a busy last couple months it's been for natural hazards and disasters! Tragically, many natural disasters have occurred worldwide, with numerous typhoons in the Pacific, earthquakes in Indonesia and the Hindu Kush, a tsunami in Samoa, and deadly wildfires in the American West. With the advent of twitter and blogging, people are increasingly turning to the web for up-to-date information on actual and potential natural hazards. We've tried to help out with twitter feed, providing up to date information, resources, and maps for natural hazards and disasters as they unfold.
In the spirit of Web 2.0 we've also decided to make NatHazMap.com more dynamic and timely by launching our own blog: NatHazMap.com News. Look to us for news on current natural hazard and disaster events, links to recently published maps of natural hazards, and current events and developments in exciting field of natural hazard mapping. We will post newer items on our home page and archive older articles on our news page. We will update as frequently as possible, with more frequent updates while natural diisaster are occuring or predicted. Also continue to follow our twitter news feed for more frequent, albeit shorter, news items. We hope you will find this new feature useful. Thanks for reading!
December 14, 2009
A flash flood warning was issued Saturday for areas near the Station Fire burn area. Areas that have recently burned are very prone to flooding, landslides, and debris flows. The fires denuded slopes of vegetation which previously intercepted rainfall and slowed runoff rates. In addition, changes in soil chemisty make large amounts of sediment available as well, increasing the risk of mud and debris flows. If you live downstream of recently burned area it is recommended that you contact local officials to help determine your risk.
Heavy rain in California has caused landslides in numerous locations. Near Mount Wilson, over 60 people were stuck in vehicles between landslides on Angeles Crest Highway. Multiple landslides were also reported on state Route 2. A rockslide and mudslide forced the CHP to briefly close Topanga Canyon Boulevard five miles north of the Pacific Coast Highway.
Another strong storm is currently forecast to affect the Pacific Northwest. At the present it appears that Southern California will be in an area of high pressure, at least for now. This should allow landslide affected residents to clean up and prepare for possible future events.
Sources: USGS, NOAA, Los Angeles Daily times
Tags: weather, landslide, wildfire
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