Some earthquake software

While I was preparing the last entry, I came across some software available through the USGS web pages.

Note that FORTRAN lives!

These are:

1. 3D Focal Mechanisms - a tool for viewing earthquake focal mechanism symbols three dimensionally
2. 3D velocity modeling
3. Cleanstrain - a program to process strainmeter data.
4. CLUSTER2000 - recognizes clusters in space-time in an earthquake catalog
5. Coulomb 3 - designed to investigate Coulomb stress changes on mapped faults and earthquake nodal planes
6. FPFIT - a Fortran program that computes double-couple fault plane solutions from P-wave first motion data
7. Ground Motion Parameter Calculator
8. HASH - a Fortran 77 code that computes double-couple earthquake focal mechanisms from P-wave first motion polarity observations
9. HypoDD - a Fortran computer program package for relocating earthquakes with the double-difference (DD) algorithm
10. HYPOINVERSE2000 - determines earthquake locations and magnitudes from seismic network data like first-arrival P and S arrival times, amplitudes and coda durations
11. MacR1D - a one-dimensional seismic travel-time calculator for Macintosh
12. MacRay - a general purpose two-dimensional seismic ray-tracer for Macintosh
13. OpenSHA - an effort to develop object-oriented, web- & GUI-enabled, open-source, and freely available code for conducting Seismic Hazard Analyses
14. PQLX - open-source software system for evaluating seismic station performance and data quality
15. Probabilistic Seismic Hazard Calculation Software
16. Quake Data Distribution System (QDDS) - provides a method for distributing earthquake data over the Internet in near-real time
17. The Quake Data Merge Real Time Merged Catalog (QDM) software
18. SATSI (Spatial And Temporal Stress Inversion) - inverts focal mechanism data for a spatially and/or temporally varying stress field
19. ShakeCast - delivers maps of areas affected by an earthquake
20. Slick Package - uses fault slip data (either field observations or from focal mechanism) to find the stress tensor that best explains the observations
21. Slope Performance During an Earthquake

Mexicali earthquake poster

The USGS has produced another in its fine series of posters on significant earthquakes.

The latest is on the magnitude 7.2 Mexicali quake.

Click on the image for a larger version

I won't dissect it in detail as I did for the Chile quake, but in the next post, we'll look at the fault plane solution, and its relation to the San Andreas Fault.

Chile aftershock report

The U.S. Geological Survey presents more interesting information on the Chile magnitude 8.8 quake here. The aftershock report notes

In the time period since the earthquake's origin at 2010-02-27 06:34 to 2010-03-15 15:00 UTC, the USGS NEIC has located 229 aftershocks of magnitude 5.0 or greater. Eighteen of these aftershocks have magnitudes of 6.0 or greater.

You've been hearing about many of these not insignificant aftershocks in the news.

Below is a current aftershock map, which can be found with updates here. Note the scale - these have been occurring along the plate boundary over a distance of about 1000 km, and over an area of about 50,000 square kilometers!

A teachable moment - the Chile earthquake

The U.S Geological Survey has already issued an informative poster on the Chile earthquake, which can be downloaded here.

Here is the first part of the poster:

You can see the past earthquakes along the subduction zone (hatched line), where the Nazca plate on the left dives beneath the South American plate on the east. The epicenter of yesterday's quake (star) is not far from the largest earthquake ever measured, from 1960. The colors denote the depth of the hypocenters.

We'll look at other parts of the poster in upcoming posts.

Haiti aftershocks expected

I don't think this will get me an manyhits as the last Disaster Porn post.
Note again all the emphasis on probabilties!

From the USGS newsroom:

RESTON, Va.—The aftershock sequence of the magnitude-7 earthquake that struck near Port-au-Prince, Haiti, on Jan. 12, 2010, will continue for months, if not years. The frequency of events will diminish with time, but damaging earthquakes will remain a threat.

U.S. Geological Survey Director Marcia McNutt asked a team of USGS earthquake scientists to provide an evaluation of the earthquakes facing Haiti now and in the future. Here is the statement in its entirety from the U.S. Geological Survey:

Earthquake Hazard and Safety in Haiti and the Caribbean Region

The magnitude-7 earthquake of January 12, 2010, near Port-au-Prince, Haiti, has generated a sharp increase in concerns about the potential for future earthquakes in Haiti and the surrounding region. These concerns extend to understanding the causes of the earthquake hazard and learning what can be done to ensure seismic safety in the future. The purpose of this statement is to convey our best judgment on these subjects.

 Aftershocks: The aftershock sequence of a magnitude-7 earthquake will continue for months if not years in the affected area. The frequency of events will diminish with time, but damaging earthquakes will remain possible in the coming months. There is also a small chance of subsequent earthquakes larger than the initial shock. The sequence from the Port-au-Prince earthquake continues to be very strong and active. Based on this activity and the statistics of aftershock sequences, our estimate for aftershock activity during a 30-day period beginning January 21, 2010, is as follows:

• The probability of one or more earthquakes of magnitude 7 or greater is less that 3 percent.
• The probability of one or more earthquakes of magnitude 6 or greater is 25 percent.
• The probability of one or more earthquakes of magnitude 5 or greater is about 90 percent.
• Approximately 2 to 3 aftershocks of magnitude 5 or greater are expected within this time period.

These estimates will be updated as new information becomes available.

Precautions: Any aftershock above magnitude 5.0 will be widely felt and has the potential to cause additional damage, particularly to vulnerable, already damaged structures. Anyone living in Haiti or involved in relief work there must maintain situational awareness with regard to their personal earthquake safety. They should always be aware of what action they are going to take if the ground starts to shake. Open spaces are generally safe but running through falling debris to get to an open space may be dangerous. Only qualified engineers can determine if a damaged building is safe for reoccupation. Until engineering assistance arrives, a general rule to follow is: If it does not look safe, it probably is not safe. Entry into or reoccupation of obviously damaged structures should be avoided.


Near-term concerns: The geologic fault that caused the Port-au-Prince earthquake is part of a seismically active zone between the North American and Caribbean tectonic plates. The earthquake undoubtedly relieved some stress on the fault segment that ruptured during the event, but the extent of rupture along the fault is unclear at this time. Fault slip models, preliminary radar surface deformation measurements, and examination of satellite and airborne imagery for surface rupture suggest that the segment of the Enriquillo fault to the east of the January-12 epicenter and directly adjacent to Port-au-Prince did not slip appreciably in this event. This implies that the Enriquillo fault zone near Port-au-Prince still stores sufficient strain to be released as a large, damaging earthquake during the lifetime of structures built during the reconstruction effort. In historic times, Haiti has experienced multiple large earthquakes, apparently on adjacent faults. We shall continue to study this situation using radar, LiDAR, and photographic data taken from satellites and aircraft. Field studies and ground observations of fault offsets during this earthquake and past events are essential to evaluating the potential for future earthquakes in proximity to Port-au-Prince.   


Long-term concerns: It is essential that the rebuilding effort in Haiti take into account the potential for, indeed the inevitability of, future strong earthquakes. Haiti is cut by two major plate boundary fault zones. Over the past three centuries, earthquakes comparable to or stronger than the recent one have struck Haiti at least four times, including those in 1751 and 1770 that destroyed Port-au-Prince. Engineers and construction professionals know how to design and build structures that will not collapse in strong earthquake shaking. Seismic hazard assessments provide the basis for the development of appropriate building codes and the identification of regions at greatest risk. A thorough seismic hazard assessment of Haiti, as well as of other countries in the Caribbean, will provide the basis for establishing or improving building codes and strengthening building resilience over the long-term. Such assessments involve geologic investigations of faults and soil conditions, reoccupation of geodetic measurement sites to determine strain accumulation, and studies of recent and historic earthquakes and seismicity patterns and statistics. These assessments usually take several years but can be accelerated to provide results markedly better than what is currently available. From these investigations, we can assess the likelihood and nature of strong shaking and ground failure over various time frames. The development of more resilient structures and infrastructure is a long-term goal, particularly in the face of economic limitations. Over the short-term, it is critical that the rebuilding effort be undertaken with an awareness of the potential for subsequent damaging events during the next months and years. It is essential that structures such as hospitals, schools, and critical facilities be reconstructed with greater resilience for the preservation of life and functionality.

Regional concerns: The experience of the Port-au-Prince, Haiti, earthquake reveals a need for better understanding of the nature and extent of earthquake and tsunami hazard in the Caribbean region. The arc of islands that forms the Lesser Antilles and Greater Antilles generally outlines the contact zone between the Caribbean and North American plates. This entire region is seismically active due to the relative motion between the plates and is prone to damaging earthquakes: a small-scale “ring of fire” like that encircling the Pacific ocean. Historical earthquakes greater than magnitude 7 have occurred in Puerto Rico, Jamaica, Dominican Republic, Martinique, and Guadeloupe. Along the northern coast of Venezuela, the juncture of the Caribbean and South American plates has caused damaging earthquakes in the vicinity of Trinidad and Tobago. Earthquake safety policy, including building codes throughout the region, should be based on thorough seismic hazard assessments.

You can access a current map of aftershocks at the M7.0 Haiti Earthquake and Aftershocks Web site, and you can listen to podcast interviews at the USGS CoreCast Web site.

U.S. Geological Survey and earthquakes in Afghanistan

An agreement between Afghanistan and the U.S. Agency for International Development and the USGS Policy Analysis and Science Assistance Branch (PASA) agreement was signed in September of 2004. This PASA initiated a USGS program in natural resources/hazards assessment for Afghanistan as part of the Afghanistan Reconstruction Program. The initial activities included coal, mineral and water resources assessments and earthquake hazard assessment. The U.S.Trade and Development Agency is also funding the USGS to conduct an oil and gas resources assessment of the country.

There are several hazards documents on the program webpage.  Included is a fact sheet on the earthquake hazard in Afghanistan.  It explains:

The nation of Afghanistan is located in a geologically active part of the world where the northward-moving Indian plate is colliding with southern part of the Eurasian plate at a rate of about 1.7 inches per year (43 mm/yr). This collision has created the world’s highest mountains and causes slips on major faults that generate large, often devastating earth- quakes. An example is the magnitude 7.6 earthquake on October 8, 2005, in Kashmir, Pakistan, which caused more than 80,000 fatalities and left an estimated 4 million people homeless.

Each year Afghanistan is struck by moderate to strong earthquakes, and every few years, a powerful earthquake causes significant damage or fatalities. As Afghanistan rebuilds following decades of war and strife, new construction and development need to be designed to accommodate the hazards posed by strong earthquakes. To assist in reconstruction efforts, the U.S. Geological Survey (USGS) has developed a preliminary seismic-hazard map of Afghanistan.

Click on the figure for a larger image.

As for the rest of the upcoming endeavors of the U.S. in Afghanistan, I tend to agree with Andrew Bacevich (see or listen to his interview on NPR, for example) that President Obama's decision to send more troops there is arbitrary and not well fitted to protecting us here at home, if indeed that is the goal.  The hope for quick success is ahistorical and based on faulty assumptions. But I guess those discussions should preoccupy other bloggers.

Recovery Act Funds to upgrade seismic networks

FOR IMMEDIATE RELEASE
Date: April 15, 2009
Contact: Joan Moody
(202) 208-6416

U.S. Department of the Interior
News Release

SAN FRANCISCO, CA – Secretary of the Interior Ken Salazar today announced the U.S. Geological Survey will fund $29.4 million in earthquake network upgrades nationwide through the American Recovery and Reinvestment Act of 2009, an investment that will significantly improve the timely delivery of information to high-hazard regions such as the Bay area.
Eat your heart out, Bobby Jindal (see earlier post).

USGS will replace old instruments – some of which have not been upgraded in 40 years – with state-of-the-art, robust systems across the highest earthquake hazard areas in California, the Pacific Northwest, Alaska, the Intermountain West, and the Central and Eastern United States.

“The timely delivery of earthquake information can mean the difference between life and death,” Salazar noted. “It requires critical infrastructure such as modern seismic networks and data processing centers so scientists can provide emergency responders with information to save lives and reduce economic losses. With nearly 75 million Americans living within earthquake prone areas, this investment is long overdue.”

Statewide, California has more than a 99 percent chance of having a magnitude 6.7 or larger earthquake within the next 30 years, according to scientists using a new model to determine the probability of big quakes. In the Bay area specifically, there is a nearly 2 out of 3 chance of an earthquake of that magnitude in that time period.

Secretary Salazar said that a significant portion of these funds can be expected to go to the state because of the high level of earthquake risk in California, the substantial existing partnerships that the USGS has with universities and the state, and the location of some of the major seismic equipment manufacturers in the state.

The funds will be used to:

• upgrade the seismic and geodetic stations that monitor earthquakes;
• improve communication systems to make them more robust and reliable;
• lay the groundwork to enable earthquake early warning – The latter is a technology in operation in Japan, Taiwan and Mexico that uses sensor detections at the earthquake epicenter to broadcast warnings to nearby areas about to be shaken;
• support students at universities in California who will be involved in the installation, providing a unique educational experience and helping to train the next generation of earthquake scientists;
• help save jobs that are threatened by cuts in state funding in California.

The USGS earthquake monitoring funds are some of the first Department of the Interior projects under the Recovery Act. Overall, the Department of the Interior and its agencies will manage $3.0 billion in investments as part of the recovery plan signed by the President to jumpstart our economy, create or save jobs, and put a down payment on addressing long-neglected challenges so our country can thrive in the 21st Century.

Eat your heart out, Bobby Jindal.

Bobby Jindal and volcano monitoring

Cartoon from Town Called Dobson

Governor Jindal, rest assured - the Shaking Earth blog takes no public funds!

Personally, I found Bobby Jindal's Republican response to President Obama's speech last week to be bankrupt of new ideas, but at least the presentation style was totally wooden and robotic.

But what about his comment on volcano monitoring? As you can read more about at Scientific American, Gov. Jindal blasted elements of the economic stimulus package as “wasteful spending”– among them, “$140 million for something called volcano monitoring” at the USGS.

“Instead of monitoring volcanoes, what Congress should be monitoring is the eruption of spending in Washington, D.C.,” Jindal said.

Congress authorized some of that $140 million to be spent on volcano monitoring, but not all of it. That line, ProPublica says, is directed to “U.S. Geological Survey facilities and equipment, including stream gages, seismic and volcano monitoring systems and national map activities.” Next thing you know, federal earthquake monitoring will be attacked.

Then we will all be New York state.

Earthquakes in New Jersey?

Great Seal of the State of New Jersey

You can get more information about earthquakes in New Jersey from the:

New Jersey Geological Survey and the

U.S. Geological Survey

NEIC post on Lancaster earthquake

The U.S. Geological Survey's Earthquake Hazards Program (aka National Earthquake Information Center) web pages have great information on earthquakes. Let's look at the information provided for the recent Lancaster earthquake.

First, the basics, to be found here, or copied below:

(click above for a larger image)

Obviously, this page gives the basic hypocenter or focus, epicenter, and magnitude information on the quake: where, when, how deep, how big, what cities was it close to (where damage might have occurred), and indicators of uncertainty and reliability. Meanings of the terms are given here; note the different types of magnitudes, perhaps the source for a future blog.