ArcGIS Explorer Blog : Earthquake

Three ways to view a good shaker

ArcGIS-Explorer-Team — Fri, 09 Jan 2009 04:24:00 GMT

Well, we were sitting around this evening wondering what our first post for 2009 would be, when the answer came in the form of a little roller coaster ride, thanks to an earthquake whose epicenter was just 6 miles from ESRI. We've covered earthquakes here on the blog plenty of times before, so we thought we'd do something a little different and take a look at the USGS earthquake data in 3 different ways as it's published at the USGS site.

First we viewed the GeoRSS feed. The connection was already stored in our list of connections since we've used that GeoRSS feed before. We just opened up the connection by choosing File > Open, and then choosing Servers in the Open Content dialog. Once we did, we could just scroll down the list of our remembered connections to find the quake feed to view it.

The feed displays all the quakes greater than magnitude 2.5 over the past day. We also used Find Address to locate ESRI, and used Measure to determine the distance from ESRI to the epicenter of the quake, which was just under 7 miles.

Next we opened the KML published on the USGS site showing all quakes greater than 1.0 in magnitude over the past 7 days. Note the display overlay in the upper left that came along with the KML, and the small aftershock (1.7 magnitude) located within a half mile of the initial temblor.

Finally we opened the USGS quake data delivered as a comma-delimited text file. We clicked on its link at the USGS site to view it in a browser, and this is what we saw:

We saved the file out as a text file, and took a look at it using Notepad. The first line in the file had field names, which was just perfect, but we had to do some minor edits to pull in the information the way we wanted. We removed quotation marks (using a global search and replace with a space) from around a combined day/date/time field, and added the extra field names to match the new formatting on the first line. We saved the file, then chose Tools > Import File to open the file import wizard.

In the first dialog we just accepted the defaults. Note the data preview panel at the bottom of this dialog which shows us how the text file is being parsed. This was especially useful since we could verify that we correctly made the edits to the file mentioned above.

After clicking Next, in the following dialog we again accepted all the defaults (the latitude and longitude fields were already found, since they had been named "lat" and "lon" in the text file) and chose "Magnitude" as the title field (so we could view it as we hovered over the location with our mouse) and "Region" as the description field.

Then we chose a symbol, and here's our map with the quake information imported from the text file.

This file contains all the magnitude 1.0 or greater quakes for the last day, and you can see there's been lots of activity in southern California during that time period.

The shakedown on the ShakeOut

ArcGIS-Explorer-Team — Fri, 14 Nov 2008 22:56:00 GMT

Yesterday nearly 5 million Californians living near the San Andreas fault participated in an earthquake disaster preparedness drill called the ShakeOut, which we mentioned in our post yesterday. The earthquake scenario included a 7.8-magnitude earthquake along a 190-mile stretch of the fault starting at the Salton Sea and stretching northwest.

To understand the demographics of the most impacted areas in the scenario, we opened the USGS earthquake simulation shake intensity map (published as a KML) and added it to Explorer. Here's the view of the quake intensity map looking north along the southern California Coast. The red areas are the areas with the highest predicted intensity.

We used the Business Reports task (powered by ESRI's Business Analyst Online), available on the Explorer Resource Center, to delineate the boundary around the highest intensity areas. We used that boundary to generate the report, shown here:

The graphic demographic profile is the one we chose, and there are many different kinds of reports to choose from (some are free, some require a subscription). The report showed that over 6 million households are located in the high intensity area, roughly evenly distributed by age and income, with %50 of the owner occupied homes having a value greater than $400,000, and %40 having a value of greater than $500,000.

The Great California ShakeOut

ArcGIS-Explorer-Team — Thu, 13 Nov 2008 16:37:00 GMT

Today at 10:00 a.m. PST marked the official beginning of the Great California ShakeOut. According to the Great Southern California ShakeOut site site the event will bring together millions of people throughout Southern California in the ShakeOut drill, the largest earthquake preparedness activity in U.S. history. The scenario depicts a magnitude 7.8 quake striking the southern San Andreas fault, and stretching north 190 miles.

One of the event sponsors is the USGS, and according to the USGS ShakeOut site the earthquake would kill 1,800 people, injure 50,000, cause $200 billion in damage, and have long-lasting social and economic consequences. The USGS site includes content and a list of resources that you can use to find data for use with ArcGIS Explorer.

We followed links at the USGS site to the USGS Land Cover Institute site where we downloaded a geotiff of the Southern California landcover from the USGS Seamless Server. The landcover shows urbanized areas, and so is an indicator of population.

We added the NLCD data to our map by going to File > Open, then choosing Rasters as our content type and adding the file we'd just downloaded. We adjusted the transparency of this layer a bit by highlighting it in the contents, and then right-clicking to choose the transparency tool.

This newly added layer was on top of others in our contents, and to add some additional context we moved the transportation layer on top using Manage Layers (Tools > Manage Layers).

Here's what our greater Redlands, California, area map looked like.

Next, we connected to the USGS earthquake magnitude 2.5 and greater GeoRSS feed. To do this we went to the USGS earthquake feeds site, and looked for the list of feeds.

We clicked the link for M 2.5+ earthquakes over the past 7 days and copied the URL. We added this feed to our map by going to File > Open and choosing Servers. At the top we clicked the GeoRSS connection, and pasted the URL into the Server input.

After we added the feed to our map, we discovered that on this ShakeOut day we've had a couple of recent temblors. Opening the popup on the feed event we can obtain additional information from the USGS site, and discover that the closest quake was a 2.8 just southeast of ESRI that took place last night shortly after 11:00 p.m.

Timely information via GeoRSS - Sneak peek at Explorer 480

ArcGIS-Explorer-Team — Wed, 14 May 2008 20:20:00 GMT

Cyclones in Myanmar. Fires in Florida. Earthquakes in China. Timely information is critical for learning about events as they happen, and subsequently how to respond and what to do in their aftermath. One of the ways that timely geographic information is published is via GeoRSS feeds.

In the upcoming Explorer 480 release GeoRSS feeds are one of the supported connections, joining ArcGIS Server, ArcIMS, and WMS.

Here we've connected to the USGS Shake Map feed, and we're showing the popup content for the 7.9 quake that hit China on Monday, May 12.

Below we've connected to another USGS GeoRSS feed publishing all the magnitude 5+ quakes worldwide. Again we're in China, in the vicinity of the disastrous 7.9 quake. You can see the strong aftershocks that followed the original temblor.

A Ringside Seat to Plate Tectonics in Action

ArcGIS-Explorer-Team — Fri, 09 May 2008 00:14:00 GMT

Just about 15 minutes ago, as the Explorer team was winding down from a series of meetings this week in a 3rd floor conference room, we felt the building shake - an earthquake!

This was a relatively minor one, only a 3.1 according to the USGS, but it was interesting to learn that its epicenter was located only 3.5 miles away from where we sat. We visited the USGS site, clicked the earthquake KML, and discovered that it was located 2.8 miles below what looks like the 3rd hole at the Redlands Country Club.

Here's a map showing the location of ESRI and the earthquake epicenter from the USGS, and the distance derived using Explorer's measure task. The quake information was updated on the USGS site just a few minutes from when we felt it.

The yellow dots are recent, but minor, quakes in the same area, the largest of which were a 2.1 and 2.2 that happened just a couple of days ago. Hmmm...

Exploring a Midwest Earthquake Zone - Continued..

ArcGIS-Explorer-Team — Thu, 01 May 2008 00:01:00 GMT

Last week we blogged about the first two parts of a four-part post on exploring the New Madrid seismic zone with ArcGIS Explorer. The final two chapters of the post have been completed, and are posted on the ESRI GIS Education Community blog.

Exploring a Midwest Earthquake Zone with Explorer

ArcGIS-Explorer-Team — Wed, 23 Apr 2008 16:13:00 GMT

Part 1 and Part 2 of a four-part blog post featuring the use of ArcGIS Explorer for taking a closer look at the New Madrid Seismic Zone have been published on ESRI's GIS Education Community Blog. Posted by George Dailey, ESRI Education Manager, it's a great example of discovering and aggregating a variety of data and using Explorer to... well... explore!

Stay tuned for Parts 3 and 4.

Taking a Look at Earthquakes (in many different ways)

ArcGIS-Explorer-Team — Fri, 18 Apr 2008 18:27:00 GMT

This morning a 5.2 quake hit Illinois, shaking a large part of the Midwest, with many aftershocks following the main temblor. The quake was believed by USGS scientists to have involved the Wabash fault, an extension of the New Madrid fault. That fault generated the 1812 New Madrid quake, one of the largest ever recorded in the US.

So this morning we took at look at things using Explorer, first connecting to an ArcIMS service found on the Geography Network. We connected to the Geography Network at www.geographynetwork.com and added the ESRI_Quake_Rec service to Explorer. That service is updated every 15 minutes by ESRI and the USGS.

We also added the USGS topo service (physical features layer) from the Explorer Resource Center (Contents > Layers) and here's how things looked.

Next we visited the USGS Hazards Program site, and downloaded the CSV file for magnitude 1+ earthquakes over the last 7 days. We used Explorer's import capabilities to create results from the lat/long coordinates to add them to our map. We chose the magnitude as the title, and date and time as the description. And below we've used the swipe tool on the topo layer to reveal the imagery underneath.

From the same site we also clicked to open the KML file.

Next, we imported the CSV file and created a file geodatabase. Why did we do that? You'll find out in a couple of paragraphs, but here's the local file geodatabase in Explorer. When we click on the earthquake location point, the attribute information for the quake is displayed.

Using the file geodatabase from above, we decided to be a little more creative. We buffered each point (to create polygons at each quake location for better visualization) then symbolized and extruded each of those polygons based on the earthquake magnitude using ArcGlobe. To make things more visually dramatic, we added a multiplier to the magnitude just to extrude the features further. We saved the ArcGlobe .3DD file, and published it via one of our ArcGIS Servers.

Here's the area around southern California, and you can clearly see that during the past week this region has been seismically active too.

Finally, we tapped into the USGS "Shakemap" GeoRSS feed for a real time feed of live earthquake information.

Now we'll have to be honest and let you know we're cheating a bit with this one, but only just a little bit. The above screenshot showing a GeoRSS connection was created using today's daily build of Explorer hot off the development machines.

For everyone else, you won't be able to connect to a GeoRSS feed using the currently released Explorer 450, but you'll be able to do everything else we've shown here. GeoRSS support is just one of the many new features we'll be releasing with Explorer 480.